diff --git a/src/base.rs b/src/base.rs
index fef5b11..49a1312 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -389,6 +389,9 @@ pub enum RoomAction {
     /// Open the members window.
     Members(Box<CommandContext>),
 
+    /// Set whether a room is a direct message.
+    SetDirect(bool),
+
     /// Set a room property.
     Set(RoomField, String),
 
diff --git a/src/commands.rs b/src/commands.rs
index d6db847..6781f1b 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -422,6 +422,14 @@ fn iamb_room(desc: CommandDescription, ctx: &mut ProgContext) -> ProgResult {
     }
 
     let act: IambAction = match (field.as_str(), action.as_str(), args.pop()) {
+        // :room dm set
+        ("dm", "set", None) => RoomAction::SetDirect(true).into(),
+        ("dm", "set", Some(_)) => return Result::Err(CommandError::InvalidArgument),
+
+        // :room dm set
+        ("dm", "unset", None) => RoomAction::SetDirect(false).into(),
+        ("dm", "unset", Some(_)) => return Result::Err(CommandError::InvalidArgument),
+
         // :room name set <room-name>
         ("name", "set", Some(s)) => RoomAction::Set(RoomField::Name, s).into(),
         ("name", "set", None) => return Result::Err(CommandError::InvalidArgument),
@@ -789,6 +797,32 @@ mod tests {
         assert_eq!(res, Err(CommandError::InvalidArgument));
     }
 
+    #[test]
+    fn test_cmd_room_dm_set() {
+        let mut cmds = setup_commands();
+        let ctx = EditContext::default();
+
+        let res = cmds.input_cmd("room dm set", ctx.clone()).unwrap();
+        let act = RoomAction::SetDirect(true);
+        assert_eq!(res, vec![(act.into(), ctx.clone())]);
+
+        let res = cmds.input_cmd("room dm set true", ctx.clone());
+        assert_eq!(res, Err(CommandError::InvalidArgument));
+    }
+
+    #[test]
+    fn test_cmd_room_dm_unset() {
+        let mut cmds = setup_commands();
+        let ctx = EditContext::default();
+
+        let res = cmds.input_cmd("room dm unset", ctx.clone()).unwrap();
+        let act = RoomAction::SetDirect(false);
+        assert_eq!(res, vec![(act.into(), ctx.clone())]);
+
+        let res = cmds.input_cmd("room dm unset true", ctx.clone());
+        assert_eq!(res, Err(CommandError::InvalidArgument));
+    }
+
     #[test]
     fn test_cmd_room_tag_set() {
         let mut cmds = setup_commands();
diff --git a/src/windows/room/mod.rs b/src/windows/room/mod.rs
index afe4547..56d13f6 100644
--- a/src/windows/room/mod.rs
+++ b/src/windows/room/mod.rs
@@ -249,6 +249,16 @@ impl RoomState {
 
                 Ok(vec![(act, cmd.context.clone())])
             },
+            RoomAction::SetDirect(is_direct) => {
+                let room = store
+                    .application
+                    .get_joined_room(self.id())
+                    .ok_or(UIError::Application(IambError::NotJoined))?;
+
+                room.set_is_direct(is_direct).await.map_err(IambError::from)?;
+
+                Ok(vec![])
+            },
             RoomAction::Set(field, value) => {
                 let room = store
                     .application