diff --git a/src/SlashCommands.tsx b/src/SlashCommands.tsx
index 6b5f261374..aedcf7af8c 100644
--- a/src/SlashCommands.tsx
+++ b/src/SlashCommands.tsx
@@ -441,15 +441,14 @@ export const Commands = [
     }),
     new Command({
         command: 'invite',
-        args: '<user-id>',
+        args: '<user-id> [<reason>]',
         description: _td('Invites user with given id to current room'),
         runFn: function(roomId, args) {
             if (args) {
-                const matches = args.match(/^(\S+)$/);
-                if (matches) {
+                const [address, reason] = args.split(/\s+(.+)/);
+                if (address) {
                     // We use a MultiInviter to re-use the invite logic, even though
                     // we're only inviting one user.
-                    const address = matches[1];
                     // If we need an identity server but don't have one, things
                     // get a bit more complex here, but we try to show something
                     // meaningful.
@@ -490,7 +489,7 @@ export const Commands = [
                     }
                     const inviter = new MultiInviter(roomId);
                     return success(prom.then(() => {
-                        return inviter.invite([address]);
+                        return inviter.invite([address], reason);
                     }).then(() => {
                         if (inviter.getCompletionState(address) !== "invited") {
                             throw new Error(inviter.getErrorText(address));
diff --git a/src/utils/MultiInviter.js b/src/utils/MultiInviter.js
index 7d1c900360..63d3942b37 100644
--- a/src/utils/MultiInviter.js
+++ b/src/utils/MultiInviter.js
@@ -53,13 +53,15 @@ export default class MultiInviter {
      * instance of the class.
      *
      * @param {array} addrs Array of addresses to invite
+     * @param {string} reason Reason for inviting (optional)
      * @returns {Promise} Resolved when all invitations in the queue are complete
      */
-    invite(addrs) {
+    invite(addrs, reason) {
         if (this.addrs.length > 0) {
             throw new Error("Already inviting/invited");
         }
         this.addrs.push(...addrs);
+        this.reason = reason;
 
         for (const addr of this.addrs) {
             if (getAddressType(addr) === null) {
@@ -123,7 +125,7 @@ export default class MultiInviter {
                 }
             }
 
-            return MatrixClientPeg.get().invite(roomId, addr);
+            return MatrixClientPeg.get().invite(roomId, addr, undefined, this.reason);
         } else {
             throw new Error('Unsupported address');
         }