Dorset & Wilts 3 South was an English Rugby Union league, forming part of the South West Division, primarily for clubs based in Dorset, sitting at tier 10 of the English rugby union system. Promoted teams generally moved up to Dorset & Wilts 2 South. Relegated teams dropped to Dorset & Wilts 4 until the cancellation of this division at the end of the 2015–16 season; after that there was no relegation. The league was created in 2005 and disbanded after the 2018–19 season.