This paper presents an x-ray diffraction and transmission electron microscopy analysis of Al1−xInxAs grown by molecular beam epitaxy. Two samples grown on (001) InP at temperatures of 370 and 400 °C are characterized. The first, which contains a high density of twin lamellae, exhibits triple-period short-range ordering with a rather short correlation range normal to the (111) planes. Within these (individual) planes, the concentration, however, is uniform over a considerably greater distance, leading to a highly anisotropic scattering. This is the first observation of triple-period short-range ordering in a sample that exhibits 2 × 1 surface reconstruction. The second sample exhibits CuPt-type short-range ordering with scattering that is significantly streaked, suggestive of lamellar-shaped ordered domains. Both samples contain high densities of stacking faults leading to additional sharp streaking along symmetry-allowed 〈111〉 directions.