Ap‐channel field‐effect transistor with a 3.5 &mgr;m Cr/Au gate was fabricated from a modulation‐doped GaAs/In0.2Ga0.8As/GaAs quantum well structure. Well‐behaved transistor action was observed at both 300 and 77 K with extrinsic transconductances of 6.2 and 11.3 mS/mm, respectively. Shubnikov–deHaas measurements prove the existence of a two‐dimensional hole gas with a strain‐shifted light‐hole ground state associated with a light‐hole mass of 0.154m0.