Mossley was never officially granted a coat-of-arms by the College of Heralds. However, the device described and shown below was used for civic purposes. The following explanation of its meaning is given in "The Story of Mossley: ancient and modern" by Alfred Holt (1974).
The Mossley coat-of-arms shows three square divisions on the top portion of the shield. The middle division contains a sheaf of corn and denotes that part of Mossley which is in Cheshire. The two side divisions show the red rose of Lancashire and the white rose of Yorkshire. The lower space of the shield is filled with a cotton plant which represents the chief industry of the town in 1885 when Mossley first became a borough. The wavy lines across indicate the River Tame. The Latin motto means 'He flourishes who labours'.