In 1921 the decision was made to perpetuate the designations and battle honours of the AIF by reforming these units as part of the Militia. In 1927 territorial titles were adopted and the battalion became the 11th Battalion (City of Perth Regiment). During the economic hardships of the 1930s the battalion was briefly amalgamated with the 16th Battalion, however, in 1936, in response to the reoccupation of the Rhineland by German military forces, the Australian government decided to expand the Militia; as a result, the two units were delinked once again.