diff --git a/src/autocomplete/AutocompleteProvider.js b/src/autocomplete/AutocompleteProvider.js
index 4c7d039da4..c93ae4fb2a 100644
--- a/src/autocomplete/AutocompleteProvider.js
+++ b/src/autocomplete/AutocompleteProvider.js
@@ -1,6 +1,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -28,6 +29,10 @@ export default class AutocompleteProvider {
         }
     }
 
+    destroy() {
+        // stub
+    }
+
     /**
      * Of the matched commands in the query, returns the first that contains or is contained by the selection, or null.
      */
diff --git a/src/autocomplete/Autocompleter.js b/src/autocomplete/Autocompleter.js
index 5b10110f04..94d2ed28de 100644
--- a/src/autocomplete/Autocompleter.js
+++ b/src/autocomplete/Autocompleter.js
@@ -1,5 +1,6 @@
 /*
 Copyright 2016 Aviral Dasgupta
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -45,41 +46,56 @@ const PROVIDERS = [
     EmojiProvider,
     CommandProvider,
     DuckDuckGoProvider,
-].map((completer) => completer.getInstance());
+];
 
 // Providers will get rejected if they take longer than this.
 const PROVIDER_COMPLETION_TIMEOUT = 3000;
 
-export async function getCompletions(query: string, selection: SelectionRange, force: boolean = false): Array<Completion> {
-    /* Note: That this waits for all providers to return is *intentional*
-     otherwise, we run into a condition where new completions are displayed
-     while the user is interacting with the list, which makes it difficult
-     to predict whether an action will actually do what is intended
-    */
-    const completionsList = await Promise.all(
-        // Array of inspections of promises that might timeout. Instead of allowing a
-        // single timeout to reject the Promise.all, reflect each one and once they've all
-        // settled, filter for the fulfilled ones
-        PROVIDERS.map((provider) => {
-            return provider
-                .getCompletions(query, selection, force)
-                .timeout(PROVIDER_COMPLETION_TIMEOUT)
-                .reflect();
-        }),
-    );
+export default class Autocompleter {
+    constructor(room) {
+        this.room = room;
+        this.providers = PROVIDERS.map((p) => {
+            return new p(room);
+        });
+    }
 
-    return completionsList.filter(
-        (inspection) => inspection.isFulfilled(),
-    ).map((completionsState, i) => {
-        return {
-            completions: completionsState.value(),
-            provider: PROVIDERS[i],
+    destroy() {
+        this.providers.forEach((p) => {
+            p.destroy();
+        });
+    }
 
-            /* the currently matched "command" the completer tried to complete
-             * we pass this through so that Autocomplete can figure out when to
-             * re-show itself once hidden.
-             */
-            command: PROVIDERS[i].getCurrentCommand(query, selection, force),
-        };
-    });
+    async getCompletions(query: string, selection: SelectionRange, force: boolean = false): Array<Completion> {
+        /* Note: This intentionally waits for all providers to return,
+         otherwise, we run into a condition where new completions are displayed
+         while the user is interacting with the list, which makes it difficult
+         to predict whether an action will actually do what is intended
+        */
+        const completionsList = await Promise.all(
+            // Array of inspections of promises that might timeout. Instead of allowing a
+            // single timeout to reject the Promise.all, reflect each one and once they've all
+            // settled, filter for the fulfilled ones
+            this.providers.map((provider) => {
+                return provider
+                    .getCompletions(query, selection, force)
+                    .timeout(PROVIDER_COMPLETION_TIMEOUT)
+                    .reflect();
+            }),
+        );
+
+        return completionsList.filter(
+            (inspection) => inspection.isFulfilled(),
+        ).map((completionsState, i) => {
+            return {
+                completions: completionsState.value(),
+                provider: this.providers[i],
+
+                /* the currently matched "command" the completer tried to complete
+                 * we pass this through so that Autocomplete can figure out when to
+                 * re-show itself once hidden.
+                 */
+                command: this.providers[i].getCurrentCommand(query, selection, force),
+            };
+        });
+    }
 }
diff --git a/src/autocomplete/CommandProvider.js b/src/autocomplete/CommandProvider.js
index e85457e6aa..d47f1a161a 100644
--- a/src/autocomplete/CommandProvider.js
+++ b/src/autocomplete/CommandProvider.js
@@ -1,6 +1,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -109,8 +110,6 @@ const COMMANDS = [
 
 const COMMAND_RE = /(^\/\w*)/g;
 
-let instance = null;
-
 export default class CommandProvider extends AutocompleteProvider {
     constructor() {
         super(COMMAND_RE);
@@ -142,12 +141,6 @@ export default class CommandProvider extends AutocompleteProvider {
         return '*️⃣ ' + _t('Commands');
     }
 
-    static getInstance(): CommandProvider {
-        if (instance === null) instance = new CommandProvider();
-
-        return instance;
-    }
-
     renderCompletions(completions: [React.Component]): ?React.Component {
         return <div className="mx_Autocomplete_Completion_container_block">
             { completions }
diff --git a/src/autocomplete/DuckDuckGoProvider.js b/src/autocomplete/DuckDuckGoProvider.js
index b2e85c4668..68d4915f56 100644
--- a/src/autocomplete/DuckDuckGoProvider.js
+++ b/src/autocomplete/DuckDuckGoProvider.js
@@ -1,6 +1,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -25,8 +26,6 @@ import {TextualCompletion} from './Components';
 const DDG_REGEX = /\/ddg\s+(.+)$/g;
 const REFERRER = 'vector';
 
-let instance = null;
-
 export default class DuckDuckGoProvider extends AutocompleteProvider {
     constructor() {
         super(DDG_REGEX);
@@ -96,13 +95,6 @@ export default class DuckDuckGoProvider extends AutocompleteProvider {
         return '🔍 ' + _t('Results from DuckDuckGo');
     }
 
-    static getInstance(): DuckDuckGoProvider {
-        if (instance == null) {
-            instance = new DuckDuckGoProvider();
-        }
-        return instance;
-    }
-
     renderCompletions(completions: [React.Component]): ?React.Component {
         return <div className="mx_Autocomplete_Completion_container_block">
             { completions }
diff --git a/src/autocomplete/EmojiProvider.js b/src/autocomplete/EmojiProvider.js
index a5b80e3b0e..9f1f40dbe7 100644
--- a/src/autocomplete/EmojiProvider.js
+++ b/src/autocomplete/EmojiProvider.js
@@ -1,6 +1,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -70,8 +71,6 @@ const EMOJI_SHORTNAMES = Object.keys(EmojiData).map((key) => EmojiData[key]).sor
     };
 });
 
-let instance = null;
-
 function score(query, space) {
     const index = space.indexOf(query);
     if (index === -1) {
@@ -151,11 +150,6 @@ export default class EmojiProvider extends AutocompleteProvider {
         return '😃 ' + _t('Emoji');
     }
 
-    static getInstance() {
-        if (instance == null) {instance = new EmojiProvider();}
-        return instance;
-    }
-
     renderCompletions(completions: [React.Component]): ?React.Component {
         return <div className="mx_Autocomplete_Completion_container_pill">
             { completions }
diff --git a/src/autocomplete/RoomProvider.js b/src/autocomplete/RoomProvider.js
index cc04f54dda..1e1928a1ee 100644
--- a/src/autocomplete/RoomProvider.js
+++ b/src/autocomplete/RoomProvider.js
@@ -1,6 +1,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -27,8 +28,6 @@ import _sortBy from 'lodash/sortBy';
 
 const ROOM_REGEX = /(?=#)(\S*)/g;
 
-let instance = null;
-
 function score(query, space) {
     const index = space.indexOf(query);
     if (index === -1) {
@@ -96,14 +95,6 @@ export default class RoomProvider extends AutocompleteProvider {
         return '💬 ' + _t('Rooms');
     }
 
-    static getInstance() {
-        if (instance == null) {
-            instance = new RoomProvider();
-        }
-
-        return instance;
-    }
-
     renderCompletions(completions: [React.Component]): ?React.Component {
         return <div className="mx_Autocomplete_Completion_container_pill mx_Autocomplete_Completion_container_truncate">
             { completions }
diff --git a/src/autocomplete/UserProvider.js b/src/autocomplete/UserProvider.js
index 296399c06c..8b43964b1a 100644
--- a/src/autocomplete/UserProvider.js
+++ b/src/autocomplete/UserProvider.js
@@ -2,6 +2,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -30,20 +31,55 @@ import type {Room, RoomMember} from 'matrix-js-sdk';
 
 const USER_REGEX = /@\S*/g;
 
-let instance = null;
-
 export default class UserProvider extends AutocompleteProvider {
     users: Array<RoomMember> = null;
     room: Room = null;
 
-    constructor() {
+    constructor(room) {
         super(USER_REGEX, {
             keys: ['name'],
         });
+        this.room = room;
         this.matcher = new FuzzyMatcher([], {
             keys: ['name', 'userId'],
             shouldMatchPrefix: true,
         });
+
+        this._onRoomTimelineBound = this._onRoomTimeline.bind(this);
+        this._onRoomStateMemberBound = this._onRoomStateMember.bind(this);
+
+        MatrixClientPeg.get().on("Room.timeline", this._onRoomTimelineBound);
+        MatrixClientPeg.get().on("RoomState.members", this._onRoomStateMemberBound);
+    }
+
+    destroy() {
+        MatrixClientPeg.get().removeListener("Room.timeline", this._onRoomTimelineBound);
+        MatrixClientPeg.get().removeListener("RoomState.members", this._onRoomStateMemberBound);
+    }
+
+    _onRoomTimeline(ev, room, toStartOfTimeline, removed, data) {
+        if (!room) return;
+        if (removed) return;
+        if (room.roomId !== this.room.roomId) return;
+
+        // ignore events from filtered timelines
+        if (data.timeline.getTimelineSet() !== room.getUnfilteredTimelineSet()) return;
+
+        // ignore anything but real-time updates at the end of the room:
+        // updates from pagination will happen when the paginate completes.
+        if (toStartOfTimeline || !data || !data.liveEvent) return;
+
+        this.onUserSpoke(ev.sender);
+    }
+
+    _onRoomStateMember(ev, state, member) {
+        // ignore members in other rooms
+        if (member.roomId !== this.room.roomId) {
+            return;
+        }
+
+        // blow away the users cache
+        this.users = null;
     }
 
     async getCompletions(query: string, selection: {start: number, end: number}, force = false) {
@@ -86,11 +122,6 @@ export default class UserProvider extends AutocompleteProvider {
         return '👥 ' + _t('Users');
     }
 
-    setUserListFromRoom(room: Room) {
-        this.room = room;
-        this.users = null;
-    }
-
     _makeUsers() {
         const events = this.room.getLiveTimeline().getEvents();
         const lastSpoken = {};
@@ -123,13 +154,6 @@ export default class UserProvider extends AutocompleteProvider {
         this.matcher.setObjects(this.users);
     }
 
-    static getInstance(): UserProvider {
-        if (instance == null) {
-            instance = new UserProvider();
-        }
-        return instance;
-    }
-
     renderCompletions(completions: [React.Component]): ?React.Component {
         return <div className="mx_Autocomplete_Completion_container_pill mx_Autocomplete_Completion_container_truncate">
             { completions }
diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index 9b6dbb4c27..a40fff274c 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -44,8 +44,6 @@ const Rooms = require('../../Rooms');
 
 import KeyCode from '../../KeyCode';
 
-import UserProvider from '../../autocomplete/UserProvider';
-
 import RoomViewStore from '../../stores/RoomViewStore';
 import RoomScrollStateStore from '../../stores/RoomScrollStateStore';
 
@@ -541,12 +539,6 @@ module.exports = React.createClass({
                 });
             }
         }
-
-        // update the tab complete list as it depends on who most recently spoke,
-        // and that has probably just changed
-        if (ev.sender) {
-            UserProvider.getInstance().onUserSpoke(ev.sender);
-        }
     },
 
     onRoomName: function(room) {
@@ -568,7 +560,6 @@ module.exports = React.createClass({
         this._warnAboutEncryption(room);
         this._calculatePeekRules(room);
         this._updatePreviewUrlVisibility(room);
-        UserProvider.getInstance().setUserListFromRoom(room);
     },
 
     _warnAboutEncryption: function(room) {
@@ -722,9 +713,6 @@ module.exports = React.createClass({
         // refresh the conf call notification state
         this._updateConfCallNotification();
 
-        // refresh the tab complete list
-        UserProvider.getInstance().setUserListFromRoom(this.state.room);
-
         // if we are now a member of the room, where we were not before, that
         // means we have finished joining a room we were previously peeking
         // into.
diff --git a/src/components/views/rooms/Autocomplete.js b/src/components/views/rooms/Autocomplete.js
index ecc908a02c..958d16073c 100644
--- a/src/components/views/rooms/Autocomplete.js
+++ b/src/components/views/rooms/Autocomplete.js
@@ -1,5 +1,23 @@
+/*
+Copyright 2016 Aviral Dasgupta
+Copyright 2017 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
 import React from 'react';
 import ReactDOM from 'react-dom';
+import PropTypes from 'prop-types';
 import classNames from 'classnames';
 import flatMap from 'lodash/flatMap';
 import isEqual from 'lodash/isEqual';
@@ -7,8 +25,9 @@ import sdk from '../../../index';
 import type {Completion} from '../../../autocomplete/Autocompleter';
 import Promise from 'bluebird';
 import UserSettingsStore from '../../../UserSettingsStore';
+import { Room } from 'matrix-js-sdk';
 
-import {getCompletions} from '../../../autocomplete/Autocompleter';
+import Autocompleter from '../../../autocomplete/Autocompleter';
 
 const COMPOSER_SELECTED = 0;
 
@@ -17,6 +36,7 @@ export default class Autocomplete extends React.Component {
     constructor(props) {
         super(props);
 
+        this.autocompleter = new Autocompleter(props.room);
         this.completionPromise = null;
         this.hide = this.hide.bind(this);
         this.onCompletionClicked = this.onCompletionClicked.bind(this);
@@ -41,6 +61,11 @@ export default class Autocomplete extends React.Component {
     }
 
     componentWillReceiveProps(newProps, state) {
+        if (this.props.room.roomId !== newProps.room.roomId) {
+            this.autocompleter.destroy();
+            this.autocompleter = new Autocompleter(newProps.room);
+        }
+
         // Query hasn't changed so don't try to complete it
         if (newProps.query === this.props.query) {
             return;
@@ -49,6 +74,10 @@ export default class Autocomplete extends React.Component {
         this.complete(newProps.query, newProps.selection);
     }
 
+    componentWillUnmount() {
+        this.autocompleter.destroy();
+    }
+
     complete(query, selection) {
         this.queryRequested = query;
         if (this.debounceCompletionsRequest) {
@@ -83,7 +112,7 @@ export default class Autocomplete extends React.Component {
     }
 
     processQuery(query, selection) {
-        return getCompletions(
+        return this.autocompleter.getCompletions(
             query, selection, this.state.forceComplete,
         ).then((completions) => {
             // Only ever process the completions for the most recent query being processed
@@ -267,8 +296,11 @@ export default class Autocomplete extends React.Component {
 
 Autocomplete.propTypes = {
     // the query string for which to show autocomplete suggestions
-    query: React.PropTypes.string.isRequired,
+    query: PropTypes.string.isRequired,
 
     // method invoked with range and text content when completion is confirmed
-    onConfirm: React.PropTypes.func.isRequired,
+    onConfirm: PropTypes.func.isRequired,
+
+    // The room in which we're autocompleting
+    room: PropTypes.instanceOf(Room),
 };
diff --git a/src/components/views/rooms/MessageComposerInput.js b/src/components/views/rooms/MessageComposerInput.js
index 4850428621..43f3aa5d88 100644
--- a/src/components/views/rooms/MessageComposerInput.js
+++ b/src/components/views/rooms/MessageComposerInput.js
@@ -1,5 +1,6 @@
 /*
 Copyright 2015, 2016 OpenMarket Ltd
+Copyright 2017 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -1130,10 +1131,12 @@ export default class MessageComposerInput extends React.Component {
                 <div className="mx_MessageComposer_autocomplete_wrapper">
                     <Autocomplete
                         ref={(e) => this.autocomplete = e}
+                        room={this.props.room}
                         onConfirm={this.setDisplayedCompletion}
                         onSelectionChange={this.setDisplayedCompletion}
                         query={this.getAutocompleteQuery(content)}
-                        selection={selection} />
+                        selection={selection}
+                    />
                 </div>
                 <div className={className}>
                     <img className="mx_MessageComposer_input_markdownIndicator mx_filterFlipColor"