Hall effect results on GaAs crystals into which Li is introduced at 500°C, as well as at higher temperatures, and subsequently removed in Ga or in air at 500°C are reported. Four acceptor ionization energies: 0.023 and 0.11 eV (previously reported), 0.05 eV and 0.14 eV are found. The two levels 0.023 and 0.05 eV are attributed to Li self‐pairs. The 0.11‐ and 0.14‐eV levels are associated with Cu possibly already present in the GaAs crystals. The 0.023‐eV level is found in crystals produced by the floating‐zone process at all temperatures of the Li diffusion. The 0.023‐eV level is also found in the horizontal Bridgman crystals when diffusion is above ∼650°C. Below ∼500°C, however, the 0.05‐eV level predominates in Bridgman crystals and the 0.023‐eV level is not observed. The origins of the various levels are discussed.