High‐speed high‐quantum‐efficiency avalanche photodiodes (APD’s) are required in the 1.0–1.4‐&mgr;m wavelength range in order to exploit the superior optical fibers now available at these wavelengths. The GaAlSb heterojunction APD’s reported here have external quantum efficiencies of 60% (without antireflection coatings), risetimes of 60 ps, and pulse widths (FWHM) of 120 ps with no evidence of a ’’back porch’’. Uniform high‐speed avalanche gains of 20 have been achieved.