Abstract Developing high‐performance p ‐type oxide semiconductors is a significant challenge in thin‐film semiconductor technology due to their complex electronic structure and the presence of compensating intrinsic defects. To this aim, an unexplored thulium (Tm) doping strategy is proposed to alter the formation energy of interstitial oxygen in p ‐type tin monoxide (SnO) with Hall mobility up to 284.0 ± 3.0 cm 2 V∙s −1 , in which a field‐effect hole mobility of 12.8 cm 2 V∙s −1 and an on/off ratio above 10 4 are achieved. Benefiting from the enhanced reliability of Tm‐doped SnO thin‐film transistors (TFTs), complementary logic circuits such as inverters, NAND, and NOR gates are constructed. The inverters exhibit an ultrahigh gain, which is close to 800, surpassing most of existing counterparts. This work unfolds novel mechanism and highlights the effectiveness of the Tm doping strategy in developing Sn‐based oxide complementary devices and circuits that meet the performance requirements of future TFTs technology.