 Just a day after returning for pre-season training with Leeds, on 28 June 2013, Morison joined former club Millwall, also of the Championship, on a season-long loan deal.On rejoining Millwall, Morison stated – "I'm pleased to be back here.If anybody has any doubts about me all I'd say is that I aim to score plenty of goals for Millwall and help this club to greater success".