The 4th Motor Brigade was a formation of the Australian Army during the interwar years and the early part of the World War II.

During World War II, the brigade was mobilised for defensive duties in December 1941, and assumed positions along the southern New South Wales coast to defend against a possible invasion.

Its headquarters was established in Paddington, Sydney with the brigade's area of responsibility stretching across southern and western New South Wales.

These regiments were based in Parramatta, Orange and Goulburn, with troops being drawn from areas previously assigned to the disbanded 3rd and 4th Light Horse Brigades.

There, the brigade was assigned a defensive role to cover the southern New South Wales coast and in the event of an invasion was to prevent an enemy force from advancing towards the Central Tablelands.