 OSullivan akatanga mwaka wa2011-12 paEvent 1 yePlayer Tour Championship, kwaakakunda 4-0 mufainari vachirwisa Joe Perry. PaPaul Hunter Classic, akaita 11th official maximum break yebasa rake, uye akaisa rekodhi nyowani yebasa rakanyanya kuputsa. Akasvika kumasemi-fainari, asi akarasikirwa ne3 × 4 naMark Selby. Mutambo wake wakatevera waiva weShanghai Masters, kwaakasvika padanho rechipiri, asi akarasikirwa ne3 kusvika ku5 naAnthony Hamilton. Muna Gumiguru 2011 akahwina Kay Suzanne Memorial Trophy, nekukunda Matthew Stevens 42 mufainari. MunaNovember 2011 akasvika kumagumo eAntwerp Open, asi akarasikirwa ne3 × 4 naJudd Trump. Mushure memitambo gumi nembiri kubva pagumi nembiri, OSullivan akaiswa pachinzvimbo chechipiri paOrder of Merit, uye akakodzera kuenda kuFinal, asi akabva nekuda kwezvikonzero zvekurapa. 