The 2011–12 South West Peninsula League season was the fifth in the history of the South West Peninsula League, a football competition in England, that feeds the Premier Division of the Western Football League.
The league had been formed in 2007 from the merger of the Devon County League and the South Western League, and is restricted to clubs based in Cornwall and Devon.
Bodmin Town won the league for the third time, but did not apply for promotion.
Buckland Athletic did apply, and were accepted into the Premier Division of the Western League.
The Premier Division featured 20 teams, the same as the previous season, after Wadebridge Town were relegated to Division One West.