The 2011–12 Welsh Football League Division Three began on 16 August 2011 and ended on 16 May 2012.
Bridgend Street were promoted from the South Wales Senior League and Undy Athletic were promoted from the Gwent County League.
Cwmamman United were relegated to the Neath & District League. Cwmbrân Town were relegated to the Gwent County League. South Gower were relegated to the Swansea Senior League. Porthcawl Town Athletic were relegated to the South Wales Senior League.
Caerau, Monmouth Town and Tata Steel were promoted to the Welsh Football League Division Two.
AFC Llwydcoed, Abertillery Bluebirds and Llangeinor were relegated from the Welsh Football League Division Two.
Llangeinor withdrew from the league in December.
Updated to games played on 16 May 2012.
Source: Welsh Football League
Rules for classification: 1) points; 2) goal difference; 3) number of goals scored
(C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished:
(Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.
*Llangeinor withdrew from the league in December 2011, their record was expunged.