diff --git a/web/components/chat/ChatContainer/ChatContainer.tsx b/web/components/chat/ChatContainer/ChatContainer.tsx
index ea6460b3f..cba0a7afb 100644
--- a/web/components/chat/ChatContainer/ChatContainer.tsx
+++ b/web/components/chat/ChatContainer/ChatContainer.tsx
@@ -30,6 +30,7 @@ export type ChatContainerProps = {
   height?: string;
   chatAvailable: boolean;
   focusInput?: boolean;
+  knownChatUserDisplayNames?: string[];
 };
 
 function shouldCollapseMessages(
@@ -92,6 +93,7 @@ export const ChatContainer: FC<ChatContainerProps> = ({
   isModerator,
   showInput,
   height,
+  knownChatUserDisplayNames,
   chatAvailable: chatEnabled,
   focusInput = true,
 }) => {
@@ -285,7 +287,11 @@ export const ChatContainer: FC<ChatContainerProps> = ({
         {MessagesTable}
         {showInput && (
           <div className={styles.chatTextField}>
-            <ChatTextField enabled={chatEnabled} focusInput={focusInput} />
+            <ChatTextField
+              enabled={chatEnabled}
+              knownChatUserDisplayNames={knownChatUserDisplayNames}
+              focusInput={focusInput}
+            />
           </div>
         )}
       </div>
diff --git a/web/components/chat/ChatTextField/ChatTextField.module.scss b/web/components/chat/ChatTextField/ChatTextField.module.scss
index 45ee52886..e1c6921fc 100644
--- a/web/components/chat/ChatTextField/ChatTextField.module.scss
+++ b/web/components/chat/ChatTextField/ChatTextField.module.scss
@@ -35,14 +35,14 @@
 
   div[role='textbox'] {
     font-size: 13px;
-		font-weight: 400;
+    font-weight: 400;
     padding: 0.3rem;
     background-color: inherit;
     border-color: var(--theme-color-components-form-field-border);
     box-shadow: 0;
     transition: box-shadow 50ms ease-in-out;
     &:focus {
-      outline: 1px solid var(--color-owncast-gray-500) !important;
+      outline: 1px solid var(--theme-color-components-form-field-background) !important;
     }
     & > p {
       margin: 0px;
@@ -54,7 +54,7 @@
   border: none;
   background: none;
   cursor: pointer;
-  padding: 0 .25rem;
+  padding: 0 0.25rem;
 }
 
 .sendButton {
@@ -63,3 +63,32 @@
   cursor: pointer;
   padding: 0 1rem;
 }
+
+.userMention {
+  display: inline;
+  font-size: 0.7rem;
+  padding: 3px;
+  margin-right: 2px;
+  margin-left: 2px;
+  border-radius: 5px;
+  color: var(--theme-color-components-form-field-text);
+  border: 0.05rem solid var(--theme-color-components-form-field-border);
+  background-color: var(--theme-color-components-form-field-background);
+}
+
+.autocompleteSelectMenu {
+  width: 120px;
+  right: '5px';
+  bottom: '5px';
+  z-index: 99999;
+
+  :global {
+    .ant-select-selection-item {
+      display: none;
+    }
+
+    .ant-select-dropdown {
+      display: block;
+    }
+  }
+}
diff --git a/web/components/chat/ChatTextField/ChatTextField.tsx b/web/components/chat/ChatTextField/ChatTextField.tsx
index ae78a7821..8a5b6560c 100644
--- a/web/components/chat/ChatTextField/ChatTextField.tsx
+++ b/web/components/chat/ChatTextField/ChatTextField.tsx
@@ -1,5 +1,6 @@
-import { Popover } from 'antd';
-import React, { FC, useMemo, useState } from 'react';
+/* eslint-disable jsx-a11y/no-static-element-interactions */
+import { Popover, Select } from 'antd';
+import React, { FC, useCallback, useMemo, useRef, useState } from 'react';
 import { useRecoilValue } from 'recoil';
 import { Transforms, createEditor, BaseEditor, Text, Descendant, Editor } from 'slate';
 import {
@@ -32,7 +33,10 @@ const SmileOutlined = dynamic(() => import('@ant-design/icons/SmileOutlined'), {
   ssr: false,
 });
 
-type CustomElement = { type: 'paragraph' | 'span'; children: CustomText[] } | ImageNode;
+type CustomElement =
+  | { type: 'paragraph' | 'span'; children: CustomText[] }
+  | ImageNode
+  | MentionElement;
 type CustomText = { text: string };
 
 type EmptyText = {
@@ -47,6 +51,12 @@ type ImageNode = {
   children: EmptyText[];
 };
 
+type MentionElement = {
+  type: 'mention';
+  name: string;
+  children: CustomText[];
+};
+
 declare module 'slate' {
   interface CustomTypes {
     Editor: BaseEditor & ReactEditor;
@@ -78,6 +88,17 @@ const Image = p => {
   );
 };
 
+const Mention = p => {
+  const { attributes, element, children } = p;
+
+  return (
+    <span {...attributes} className={styles.userMention} contentEditable={false}>
+      @{element.name}&nbsp;
+      {children}
+    </span>
+  );
+};
+
 const withImages = editor => {
   const { isVoid } = editor;
 
@@ -89,6 +110,17 @@ const withImages = editor => {
   return editor;
 };
 
+const withMentions = editor => {
+  const { isInline, isVoid } = editor;
+
+  // eslint-disable-next-line no-param-reassign
+  editor.isInline = element => (element.type === 'mention' ? true : isInline(element));
+  // eslint-disable-next-line no-param-reassign
+  editor.isVoid = element => (element.type === 'mention' ? true : isVoid(element));
+
+  return editor;
+};
+
 const serialize = node => {
   if (Text.isText(node)) {
     const string = node.text;
@@ -107,6 +139,8 @@ const serialize = node => {
       return `<p>${children}</p>`;
     case 'image':
       return `<img src="${node.src}" alt="${node.alt}" title="${node.name}" class="emoji"/>`;
+    case 'mention':
+      return `@${node.name}&nbsp;`;
     default:
       return children;
   }
@@ -116,6 +150,8 @@ const getCharacterCount = node => {
   if (Text.isText(node)) {
     return node.text.length;
   }
+
+  // Hard code each image to count as 5 characters.
   if (node.type === 'image') {
     return 5;
   }
@@ -132,15 +168,29 @@ export type ChatTextFieldProps = {
   defaultText?: string;
   enabled: boolean;
   focusInput: boolean;
+  knownChatUserDisplayNames?: string[];
 };
 
 const characterLimit = 300;
 
-export const ChatTextField: FC<ChatTextFieldProps> = ({ defaultText, enabled, focusInput }) => {
+export const ChatTextField: FC<ChatTextFieldProps> = ({
+  defaultText,
+  enabled,
+  focusInput,
+  knownChatUserDisplayNames,
+}) => {
   const [showEmojis, setShowEmojis] = useState(false);
   const [characterCount, setCharacterCount] = useState(defaultText?.length);
+  const [showingAutoCompleteMenu, setShowingAutoCompleteMenu] = useState(false);
   const websocketService = useRecoilValue<WebsocketService>(websocketServiceAtom);
-  const editor = useMemo(() => withReact(withImages(createEditor())), []);
+  const editor = useMemo(() => withReact(withMentions(withImages(createEditor()))), []);
+  const inputRef = useRef<HTMLDivElement>(null);
+
+  const [search, setSearch] = useState('');
+
+  const chatUserNames = knownChatUserDisplayNames
+    ?.filter(c => c.toLowerCase().startsWith(search.toLowerCase()))
+    .slice(0, 10);
 
   const defaultEditorValue: Descendant[] = [
     {
@@ -187,6 +237,16 @@ export const ChatTextField: FC<ChatTextFieldProps> = ({ defaultText, enabled, fo
     Editor.normalize(editor, { force: true });
   };
 
+  const insertMention = (e, chatDisplayName) => {
+    const mention: MentionElement = {
+      type: 'mention',
+      name: chatDisplayName,
+      children: [{ text: '' }],
+    };
+    Transforms.insertNodes(e, mention);
+    Transforms.move(e);
+  };
+
   // Native emoji
   const onEmojiSelect = (emoji: string) => {
     ReactEditor.focus(editor);
@@ -198,29 +258,32 @@ export const ChatTextField: FC<ChatTextFieldProps> = ({ defaultText, enabled, fo
     insertImage(emoji, name);
   };
 
-  const onKeyDown = (e: React.KeyboardEvent) => {
-    const charCount = getCharacterCount(editor) + 1;
+  const onKeyDown = useCallback(
+    e => {
+      const charCount = getCharacterCount(editor) + 1;
 
-    // Send the message when hitting enter.
-    if (e.key === 'Enter') {
-      e.preventDefault();
-      sendMessage();
-      return;
-    }
+      // Send the message when hitting enter.
+      if (e.key === 'Enter') {
+        e.preventDefault();
+        sendMessage();
+        return;
+      }
 
-    // Always allow backspace.
-    if (e.key === 'Backspace') {
-      setCharacterCount(charCount - 1);
-      return;
-    }
+      // Always allow backspace.
+      if (e.key === 'Backspace') {
+        setCharacterCount(charCount - 1);
+        return;
+      }
 
-    // Limit the number of characters.
-    if (charCount + 1 > characterLimit) {
-      e.preventDefault();
-    }
+      // Limit the number of characters.
+      if (charCount + 1 > characterLimit) {
+        e.preventDefault();
+      }
 
-    setCharacterCount(charCount + 1);
-  };
+      setCharacterCount(charCount + 1);
+    },
+    [editor],
+  );
 
   const onPaste = (e: React.ClipboardEvent) => {
     const text = e.clipboardData.getData('text/plain');
@@ -235,6 +298,10 @@ export const ChatTextField: FC<ChatTextFieldProps> = ({ defaultText, enabled, fo
     switch (p.element.type) {
       case 'image':
         return <Image {...p} />;
+
+      case 'mention':
+        return <Mention {...p} />;
+
       default:
         return <p {...p} />;
     }
@@ -243,12 +310,36 @@ export const ChatTextField: FC<ChatTextFieldProps> = ({ defaultText, enabled, fo
   return (
     <div id="chat-input" className={styles.root}>
       <div
+        ref={inputRef}
         className={classNames(
           styles.inputWrap,
           characterCount >= characterLimit && styles.maxCharacters,
         )}
       >
-        <Slate editor={editor} initialValue={defaultEditorValue}>
+        <Slate
+          editor={editor}
+          initialValue={defaultEditorValue}
+          onChange={() => {
+            const { selection } = editor;
+
+            if (selection && Range.isCollapsed(selection)) {
+              const [start] = Range.edges(selection);
+              const wordBefore = Editor.before(editor, start, { unit: 'word' });
+              const before = wordBefore && Editor.before(editor, wordBefore);
+              const beforeRange = before && Editor.range(editor, before, start);
+              const beforeText = beforeRange && Editor.string(editor, beforeRange);
+              const beforeMatch = beforeText && beforeText.match(/^@(\w+)$/);
+              const after = Editor.after(editor, start);
+              const afterRange = Editor.range(editor, start, after);
+              const afterText = Editor.string(editor, afterRange);
+              const afterMatch = afterText.match(/^(\s|$)/);
+
+              if (beforeMatch && afterMatch) {
+                setShowingAutoCompleteMenu(true);
+              }
+            }
+          }}
+        >
           <Editable
             className="chat-text-input"
             onKeyDown={onKeyDown}
@@ -284,6 +375,34 @@ export const ChatTextField: FC<ChatTextFieldProps> = ({ defaultText, enabled, fo
             onOpenChange={open => setShowEmojis(open)}
             open={showEmojis}
           />
+          {showingAutoCompleteMenu && (
+            <Select
+              defaultOpen
+              open
+              showArrow={false}
+              bordered={false}
+              dropdownMatchSelectWidth={false}
+              placement="topRight"
+              className={styles.autocompleteSelectMenu}
+              options={chatUserNames?.map(char => ({
+                value: char,
+                label: char,
+              }))}
+              onSelect={value => {
+                // Transforms.select(editor, target);
+                insertMention(editor, value);
+                setShowingAutoCompleteMenu(false);
+              }}
+              onInputKeyDown={e => {
+                if (e.key === 'Escape') {
+                  setShowingAutoCompleteMenu(false);
+                }
+              }}
+              // style={{ zIndex: 9999 }}
+              getPopupContainer={() => inputRef.current}
+              onBlur={() => setShowingAutoCompleteMenu(false)}
+            />
+          )}
         </Slate>
 
         {enabled && (
diff --git a/web/components/stores/ClientConfigStore.tsx b/web/components/stores/ClientConfigStore.tsx
index f093dfcf9..78616c95e 100644
--- a/web/components/stores/ClientConfigStore.tsx
+++ b/web/components/stores/ClientConfigStore.tsx
@@ -1,3 +1,4 @@
+/* eslint-disable no-case-declarations */
 import { FC, useContext, useEffect, useState } from 'react';
 import { atom, selector, useRecoilState, useSetRecoilState, RecoilEnv } from 'recoil';
 import { useMachine } from '@xstate/react';
@@ -113,6 +114,11 @@ const removedMessageIdsAtom = atom<string[]>({
   default: [],
 });
 
+export const knownChatUserDisplayNamesAtom = atom<string[]>({
+  key: 'knownChatUserDisplayNames',
+  default: [],
+});
+
 export const isChatAvailableSelector = selector({
   key: 'isChatAvailableSelector',
   get: ({ get }) => {
@@ -171,6 +177,7 @@ export const ClientConfigStore: FC = () => {
   const setGlobalFatalErrorMessage = useSetRecoilState<DisplayableError>(fatalErrorStateAtom);
   const setWebsocketService = useSetRecoilState<WebsocketService>(websocketServiceAtom);
   const [hiddenMessageIds, setHiddenMessageIds] = useRecoilState<string[]>(removedMessageIdsAtom);
+  const setKnownChatUserDisplayNames = useSetRecoilState<string[]>(knownChatUserDisplayNamesAtom);
   const [hasLoadedConfig, setHasLoadedConfig] = useState(false);
 
   let ws: WebsocketService;
@@ -291,6 +298,10 @@ export const ClientConfigStore: FC = () => {
     hasWebsocketDisconnected = false;
   };
 
+  const handleChatUserDisplayNameAdd = (displayName: string) => {
+    setKnownChatUserDisplayNames(currentState => [...currentState, displayName]);
+  };
+
   const handleMessage = (message: SocketEvent) => {
     switch (message.type) {
       case MessageType.ERROR_NEEDS_REGISTRATION:
@@ -304,6 +315,7 @@ export const ClientConfigStore: FC = () => {
         );
         if (message as ChatEvent) {
           const m = new ChatEvent(message);
+          handleChatUserDisplayNameAdd(m.user.displayName);
           if (!hasBeenModeratorNotified && m.user?.isModerator) {
             setChatMessages(currentState => [...currentState, message as ChatEvent]);
             hasBeenModeratorNotified = true;
@@ -313,6 +325,8 @@ export const ClientConfigStore: FC = () => {
         break;
       case MessageType.CHAT:
         setChatMessages(currentState => [...currentState, message as ChatEvent]);
+        const m = new ChatEvent(message);
+        handleChatUserDisplayNameAdd(m.user.displayName);
         break;
       case MessageType.NAME_CHANGE:
         handleNameChangeEvent(message as ChatEvent, setChatMessages);
diff --git a/web/components/ui/Content/Content.tsx b/web/components/ui/Content/Content.tsx
index 5bb6e5eaa..e095ad281 100644
--- a/web/components/ui/Content/Content.tsx
+++ b/web/components/ui/Content/Content.tsx
@@ -17,7 +17,11 @@ import {
   isOnlineSelector,
   isMobileAtom,
   serverStatusState,
+<<<<<<< HEAD
   isChatAvailableSelector,
+=======
+  knownChatUserDisplayNamesAtom,
+>>>>>>> 490f5dc79 (WIP chat user auto complete)
 } from '../../stores/ClientConfigStore';
 import { ClientConfig } from '../../../interfaces/client-config.model';
 
@@ -98,7 +102,11 @@ export const Content: FC = () => {
   const [isMobile, setIsMobile] = useRecoilState<boolean | undefined>(isMobileAtom);
   const messages = useRecoilValue<ChatMessage[]>(chatMessagesAtom);
   const online = useRecoilValue<boolean>(isOnlineSelector);
+<<<<<<< HEAD
   const isChatAvailable = useRecoilValue<boolean>(isChatAvailableSelector);
+=======
+  const knownChatUserDisplayNames = useRecoilValue(knownChatUserDisplayNamesAtom);
+>>>>>>> 490f5dc79 (WIP chat user auto complete)
 
   const { viewerCount, lastConnectTime, lastDisconnectTime, streamTitle } =
     useRecoilValue<ServerStatus>(serverStatusState);
@@ -268,7 +276,12 @@ export const Content: FC = () => {
               extraPageContent={extraPageContent}
               setShowFollowModal={setShowFollowModal}
               supportFediverseFeatures={supportFediverseFeatures}
+<<<<<<< HEAD
               online={online}
+=======
+              chatEnabled={isChatAvailable}
+              knownChatUserDisplayNames={knownChatUserDisplayNames}
+>>>>>>> 490f5dc79 (WIP chat user auto complete)
             />
           ) : (
             <Col span={24} style={{ paddingRight: dynamicPadding }}>
diff --git a/web/components/ui/Sidebar/Sidebar.tsx b/web/components/ui/Sidebar/Sidebar.tsx
index 1b20b95f5..708336ca3 100644
--- a/web/components/ui/Sidebar/Sidebar.tsx
+++ b/web/components/ui/Sidebar/Sidebar.tsx
@@ -8,6 +8,7 @@ import styles from './Sidebar.module.scss';
 
 import {
   currentUserAtom,
+  knownChatUserDisplayNamesAtom,
   visibleChatMessagesSelector,
   isChatAvailableSelector,
 } from '../../stores/ClientConfigStore';
@@ -24,6 +25,7 @@ export const Sidebar: FC = () => {
   const currentUser = useRecoilValue(currentUserAtom);
   const messages = useRecoilValue<ChatMessage[]>(visibleChatMessagesSelector);
   const isChatAvailable = useRecoilValue(isChatAvailableSelector);
+  const knownChatUserDisplayNames = useRecoilValue(knownChatUserDisplayNamesAtom);
 
   if (!currentUser) {
     return (
@@ -43,6 +45,7 @@ export const Sidebar: FC = () => {
         isModerator={isModerator}
         chatAvailable={isChatAvailable}
         showInput={!!currentUser}
+        knownChatUserDisplayNames={knownChatUserDisplayNames}
       />
     </Sider>
   );
diff --git a/web/pages/embed/chat/readonly/index.tsx b/web/pages/embed/chat/readonly/index.tsx
index 282b9a851..dfcfc9c1e 100644
--- a/web/pages/embed/chat/readonly/index.tsx
+++ b/web/pages/embed/chat/readonly/index.tsx
@@ -5,6 +5,7 @@ import { ChatContainer } from '../../../../components/chat/ChatContainer/ChatCon
 import {
   ClientConfigStore,
   currentUserAtom,
+  knownChatUserDisplayNamesAtom,
   visibleChatMessagesSelector,
   isChatAvailableSelector,
 } from '../../../../components/stores/ClientConfigStore';
@@ -15,6 +16,7 @@ export default function ReadOnlyChatEmbed() {
   const currentUser = useRecoilValue(currentUserAtom);
   const messages = useRecoilValue<ChatMessage[]>(visibleChatMessagesSelector);
   const isChatAvailable = useRecoilValue(isChatAvailableSelector);
+  const knownChatUserDisplayNames = useRecoilValue(knownChatUserDisplayNamesAtom);
 
   return (
     <div>
@@ -35,6 +37,7 @@ export default function ReadOnlyChatEmbed() {
             showInput={false}
             height="100vh"
             chatAvailable={isChatAvailable}
+            knownChatUserDisplayNames={knownChatUserDisplayNames}
           />
         )}
       </ErrorBoundary>
diff --git a/web/pages/embed/chat/readwrite/index.tsx b/web/pages/embed/chat/readwrite/index.tsx
index 6b7fbfc59..d278ec1c8 100644
--- a/web/pages/embed/chat/readwrite/index.tsx
+++ b/web/pages/embed/chat/readwrite/index.tsx
@@ -10,6 +10,7 @@ import {
   visibleChatMessagesSelector,
   clientConfigStateAtom,
   appStateAtom,
+  knownChatUserDisplayNamesAtom,
   serverStatusState,
   isChatAvailableSelector,
 } from '../../../../components/stores/ClientConfigStore';
@@ -28,6 +29,7 @@ export default function ReadWriteChatEmbed() {
 
   const appState = useRecoilValue<AppStateOptions>(appStateAtom);
   const isChatAvailable = useRecoilValue(isChatAvailableSelector);
+  const knownChatUserDisplayNames = useRecoilValue(knownChatUserDisplayNamesAtom);
 
   const { name, chatDisabled } = clientConfig;
   const { videoAvailable } = appState;
@@ -73,6 +75,7 @@ export default function ReadWriteChatEmbed() {
               showInput
               height="92vh"
               chatAvailable={isChatAvailable}
+              knownChatUserDisplayNames={knownChatUserDisplayNames}
             />
           </div>
         )}