Through the 20th Light Horse Regiment, the unit drew lineage back to early Victorian colonial forces, raised in 1885.

[2] The 7th had been raised in 1902 from the Victorian volunteer forces which had previously contributed personnel to contingents deployed by the state as part of the Imperial Bushmen to the Second Boer War.

[3][4][5] In 1921, the Australian Army was reorganised following the demobilisation of the wartime forces,[6] and the 20th Light Horse Regiment was assigned to the 3rd Cavalry Brigade, as a part-time unit based in Victoria.

[7] During the interwar years, the 20th Light Horse Regiment maintained depots in Seymour, Shepparton, Tatura, Melbourne, Yea, Mansfield, Alexandra, Numurkah, Broadford, Tocumwal, Finley and Nathalia, and formed part of the 2nd Cavalry Division.

[8] In the early part of World War II, the 20th Light Horse Regiment drew personnel from the Murray River region of Victoria, and in December 1941 was mobilised for full time service.

Assigned a defensive role to protect Melbourne in the event of an invasion, they were tasked with securing landing beaches around Barwon Heads and Anglesea.

[11] In this role, it was assigned to defend the airfield from a potential Japanese attack aimed at the Allied western flank.

[2] In the post war period, the unit was perpetuated by the 8th/13th Victorian Mounted Rifles,[14] which remained on the order of battle until the early 1990s when it was merged with the 4th/19th Prince of Wales's Light Horse.