Phosphagallenes (1 a/1 b) featuring double bonds between phosphorus and gallium were synthesized by reaction of (phosphanyl)phosphaketenes with the gallium carbenoid Ga(Nacnac) (Nacnac=HCC(Me)N(2,6‐i‐Pr2C6H3)2). The stability of these species is dependent on the saturation of the phosphanyl moiety. 1 a, which bears an unsaturated phosphanyl ring, rearranges in solution to yield a spirocyclic compound (2) which contains a P=P bond. The saturated variant 1 b is stable even at elevated temperatures. 1 b behaves as a frustrated Lewis pair capable of activation of H2 and forms a 1:1 adduct with CO2. We describe the synthesis of compounds exhibiting gallium–phosphorus double bonds. The stability of these species is dependent on the saturation of the phosphanyl moiety, and the saturated variant behaves as a frustrated Lewis pair that is capable of activating H2 and forms a 1:1 adduct with CO2.