diff --git a/package.json b/package.json
index e709662020..745f82d7bc 100644
--- a/package.json
+++ b/package.json
@@ -81,6 +81,7 @@
     "gemini-scrollbar": "github:matrix-org/gemini-scrollbar#91e1e566",
     "gfm.css": "^1.1.1",
     "glob": "^5.0.14",
+    "glob-to-regexp": "^0.4.1",
     "highlight.js": "^9.15.8",
     "is-ip": "^2.0.0",
     "isomorphic-fetch": "^2.2.1",
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index e909f49159..770f4723ef 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -389,6 +389,8 @@
     "Call invitation": "Call invitation",
     "Messages sent by bot": "Messages sent by bot",
     "When rooms are upgraded": "When rooms are upgraded",
+    "My Ban List": "My Ban List",
+    "This is your list of users/servers you have blocked - don't leave the room!": "This is your list of users/servers you have blocked - don't leave the room!",
     "Active call (%(roomName)s)": "Active call (%(roomName)s)",
     "unknown caller": "unknown caller",
     "Incoming voice call from %(name)s": "Incoming voice call from %(name)s",
diff --git a/src/mjolnir/BanList.js b/src/mjolnir/BanList.js
new file mode 100644
index 0000000000..6ebc0a7e36
--- /dev/null
+++ b/src/mjolnir/BanList.js
@@ -0,0 +1,98 @@
+/*
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+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.
+*/
+
+// Inspiration largely taken from Mjolnir itself
+
+import {ListRule, RECOMMENDATION_BAN, recommendationToStable} from "./ListRule";
+import MatrixClientPeg from "../MatrixClientPeg";
+
+export const RULE_USER = "m.room.rule.user";
+export const RULE_ROOM = "m.room.rule.room";
+export const RULE_SERVER = "m.room.rule.server";
+
+export const USER_RULE_TYPES = [RULE_USER, "org.matrix.mjolnir.rule.user"];
+export const ROOM_RULE_TYPES = [RULE_ROOM, "org.matrix.mjolnir.rule.room"];
+export const SERVER_RULE_TYPES = [RULE_SERVER, "org.matrix.mjolnir.rule.server"];
+export const ALL_RULE_TYPES = [...USER_RULE_TYPES, ...ROOM_RULE_TYPES, ...SERVER_RULE_TYPES];
+
+export function ruleTypeToStable(rule: string, unstable = true): string {
+    if (USER_RULE_TYPES.includes(rule)) return unstable ? USER_RULE_TYPES[USER_RULE_TYPES.length - 1] : RULE_USER;
+    if (ROOM_RULE_TYPES.includes(rule)) return unstable ? ROOM_RULE_TYPES[ROOM_RULE_TYPES.length - 1] : RULE_ROOM;
+    if (SERVER_RULE_TYPES.includes(rule)) return unstable ? SERVER_RULE_TYPES[SERVER_RULE_TYPES.length - 1] : RULE_SERVER;
+    return null;
+}
+
+export class BanList {
+    _rules: ListRule[] = [];
+    _roomId: string;
+
+    constructor(roomId: string) {
+        this._roomId = roomId;
+        this.updateList();
+    }
+
+    get roomId(): string {
+        return this._roomId;
+    }
+
+    get serverRules(): ListRule[] {
+        return this._rules.filter(r => r.kind === RULE_SERVER);
+    }
+
+    get userRules(): ListRule[] {
+        return this._rules.filter(r => r.kind === RULE_USER);
+    }
+
+    get roomRules(): ListRule[] {
+        return this._rules.filter(r => r.kind === RULE_ROOM);
+    }
+
+    banEntity(kind: string, entity: string, reason: string): Promise<any> {
+        return MatrixClientPeg.get().sendStateEvent(this._roomId, ruleTypeToStable(kind, true), {
+            entity: entity,
+            reason: reason,
+            recommendation: recommendationToStable(RECOMMENDATION_BAN, true),
+        }, "rule:" + entity);
+    }
+
+    unbanEntity(kind: string, entity: string): Promise<any> {
+        // Empty state event is effectively deleting it.
+        return MatrixClientPeg.get().sendStateEvent(this._roomId, ruleTypeToStable(kind, true), {}, "rule:" + entity);
+    }
+
+    updateList() {
+        this._rules = [];
+
+        const room = MatrixClientPeg.get().getRoom(this._roomId);
+        if (!room) return;
+
+        for (const eventType of ALL_RULE_TYPES) {
+            const events = room.currentState.getStateEvents(eventType, undefined);
+            for (const ev of events) {
+                if (!ev['state_key']) continue;
+
+                const kind = ruleTypeToStable(eventType, false);
+
+                const entity = ev.getContent()['entity'];
+                const recommendation = ev.getContent()['recommendation'];
+                const reason = ev.getContent()['reason'];
+                if (!entity || !recommendation || !reason) continue;
+
+                this._rules.push(new ListRule(entity, recommendation, reason, kind));
+            }
+        }
+    }
+}
diff --git a/src/mjolnir/ListRule.js b/src/mjolnir/ListRule.js
new file mode 100644
index 0000000000..d33248d24c
--- /dev/null
+++ b/src/mjolnir/ListRule.js
@@ -0,0 +1,63 @@
+/*
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+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 {MatrixGlob} from "../utils/MatrixGlob";
+
+// Inspiration largely taken from Mjolnir itself
+
+export const RECOMMENDATION_BAN = "m.ban";
+export const RECOMMENDATION_BAN_TYPES = [RECOMMENDATION_BAN, "org.matrix.mjolnir.ban"];
+
+export function recommendationToStable(recommendation: string, unstable = true): string {
+    if (RECOMMENDATION_BAN_TYPES.includes(recommendation)) return unstable ? RECOMMENDATION_BAN_TYPES[RECOMMENDATION_BAN_TYPES.length - 1] : RECOMMENDATION_BAN;
+    return null;
+}
+
+export class ListRule {
+    _glob: MatrixGlob;
+    _entity: string;
+    _action: string;
+    _reason: string;
+    _kind: string;
+
+    constructor(entity: string, action: string, reason: string, kind: string) {
+        this._glob = new MatrixGlob(entity);
+        this._entity = entity;
+        this._action = recommendationToStable(action, false);
+        this._reason = reason;
+        this._kind = kind;
+    }
+
+    get entity(): string {
+        return this._entity;
+    }
+
+    get reason(): string {
+        return this._reason;
+    }
+
+    get kind(): string {
+        return this._kind;
+    }
+
+    get recommendation(): string {
+        return this._action;
+    }
+
+    isMatch(entity: string): boolean {
+        return this._glob.test(entity);
+    }
+}
diff --git a/src/mjolnir/Mjolnir.js b/src/mjolnir/Mjolnir.js
new file mode 100644
index 0000000000..a12534592d
--- /dev/null
+++ b/src/mjolnir/Mjolnir.js
@@ -0,0 +1,122 @@
+/*
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+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 MatrixClientPeg from "../MatrixClientPeg";
+import {ALL_RULE_TYPES, BanList} from "./BanList";
+import SettingsStore, {SettingLevel} from "../settings/SettingsStore";
+import {_t} from "../languageHandler";
+
+// TODO: Move this and related files to the js-sdk or something once finalized.
+
+export class Mjolnir {
+    static _instance: Mjolnir = null;
+
+    _lists: BanList[] = [];
+    _roomIds: string[] = [];
+    _mjolnirWatchRef = null;
+
+    constructor() {
+    }
+
+    start() {
+        this._updateLists(SettingsStore.getValue("mjolnirRooms"));
+        this._mjolnirWatchRef = SettingsStore.watchSetting("mjolnirRooms", null, this._onListsChanged.bind(this));
+
+        MatrixClientPeg.get().on("RoomState.events", this._onEvent.bind(this));
+    }
+
+    stop() {
+        SettingsStore.unwatchSetting(this._mjolnirWatchRef);
+        MatrixClientPeg.get().removeListener("RoomState.events", this._onEvent.bind(this));
+    }
+
+    async getOrCreatePersonalList(): Promise<BanList> {
+        let personalRoomId = SettingsStore.getValue("mjolnirPersonalRoom");
+        if (!personalRoomId) {
+            const resp = await MatrixClientPeg.get().createRoom({
+                name: _t("My Ban List"),
+                topic: _t("This is your list of users/servers you have blocked - don't leave the room!"),
+                preset: "private_chat"
+            });
+            personalRoomId = resp['room_id'];
+            SettingsStore.setValue("mjolnirPersonalRoom", null, SettingLevel.ACCOUNT, personalRoomId);
+            SettingsStore.setValue("mjolnirRooms", null, SettingLevel.ACCOUNT, [personalRoomId, ...this._roomIds]);
+        }
+        if (!personalRoomId) {
+            throw new Error("Error finding a room ID to use");
+        }
+
+        let list = this._lists.find(b => b.roomId === personalRoomId);
+        if (!list) list = new BanList(personalRoomId);
+        // we don't append the list to the tracked rooms because it should already be there.
+        // we're just trying to get the caller some utility access to the list
+
+        return list;
+    }
+
+    _onEvent(event) {
+        if (!this._roomIds.includes(event.getRoomId())) return;
+        if (!ALL_RULE_TYPES.includes(event.getType())) return;
+
+        this._updateLists(this._roomIds);
+    }
+
+    _onListsChanged(settingName, roomId, atLevel, newValue) {
+        // We know that ban lists are only recorded at one level so we don't need to re-eval them
+        this._updateLists(newValue);
+    }
+
+    _updateLists(listRoomIds: string[]) {
+        this._lists = [];
+        this._roomIds = listRoomIds || [];
+        if (!listRoomIds) return;
+
+        for (const roomId of listRoomIds) {
+            // Creating the list updates it
+            this._lists.push(new BanList(roomId));
+        }
+    }
+
+    isServerBanned(serverName: string): boolean {
+        for (const list of this._lists) {
+            for (const rule of list.serverRules) {
+                if (rule.isMatch(serverName)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    isUserBanned(userId: string): boolean {
+        for (const list of this._lists) {
+            for (const rule of list.userRules) {
+                if (rule.isMatch(userId)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    static sharedInstance(): Mjolnir {
+        if (!Mjolnir._instance) {
+            Mjolnir._instance = new Mjolnir();
+        }
+        return Mjolnir._instance;
+    }
+}
+
diff --git a/src/utils/MatrixGlob.js b/src/utils/MatrixGlob.js
new file mode 100644
index 0000000000..cf55040625
--- /dev/null
+++ b/src/utils/MatrixGlob.js
@@ -0,0 +1,54 @@
+/*
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+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 * as globToRegexp from "glob-to-regexp";
+
+// Taken with permission from matrix-bot-sdk:
+// https://github.com/turt2live/matrix-js-bot-sdk/blob/eb148c2ecec7bf3ade801d73deb43df042d55aef/src/MatrixGlob.ts
+
+/**
+ * Represents a common Matrix glob. This is commonly used
+ * for server ACLs and similar functions.
+ */
+export class MatrixGlob {
+    _regex: RegExp;
+
+    /**
+     * Creates a new Matrix Glob
+     * @param {string} glob The glob to convert. Eg: "*.example.org"
+     */
+    constructor(glob: string) {
+        const globRegex = globToRegexp(glob, {
+            extended: false,
+            globstar: false,
+        });
+
+        // We need to convert `?` manually because globToRegexp's extended mode
+        // does more than we want it to.
+        const replaced = globRegex.toString().replace(/\\\?/g, ".");
+        this._regex = new RegExp(replaced.substring(1, replaced.length - 1));
+    }
+
+    /**
+     * Tests the glob against a value, returning true if it matches.
+     * @param {string} val The value to test.
+     * @returns {boolean} True if the value matches the glob, false otherwise.
+     */
+    test(val: string): boolean {
+        return this._regex.test(val);
+    }
+
+}
diff --git a/yarn.lock b/yarn.lock
index aa0a06e588..a2effb975c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3674,6 +3674,11 @@ glob-to-regexp@^0.3.0:
   resolved "https://registry.yarnpkg.com/glob-to-regexp/-/glob-to-regexp-0.3.0.tgz#8c5a1494d2066c570cc3bfe4496175acc4d502ab"
   integrity sha1-jFoUlNIGbFcMw7/kSWF1rMTVAqs=
 
+glob-to-regexp@^0.4.1:
+  version "0.4.1"
+  resolved "https://registry.yarnpkg.com/glob-to-regexp/-/glob-to-regexp-0.4.1.tgz#c75297087c851b9a578bd217dd59a92f59fe546e"
+  integrity sha512-lkX1HJXwyMcprw/5YUZc2s7DrpAiHB21/V+E1rHUrVNokkvB6bqMzT0VfV6/86ZNabt1k14YOIaT7nDvOX3Iiw==
+
 glob@7.1.2:
   version "7.1.2"
   resolved "https://registry.yarnpkg.com/glob/-/glob-7.1.2.tgz#c19c9df9a028702d678612384a6552404c636d15"