Antelope Valley is a wedge-shaped basin on the boundary between the Coast Ranges and the Basin and Range province, and shows structural features of both. It is underlain by Tertiary marine and non-marine sediments and volcanics, and bounded by ranges composed of crystalline rocks. Its form is outlined by the northeast-trending Garlock fault zone and the southeast-trending San Andreas rift, both major lines of weakness. Between these faults, smaller faults of northeast and northwest trends break the rocks of Antelope Valley into at least a dozen tilted blocks. Left-lateral movement is demonstrated on several of the smaller faults which branch from the Garlock, and it is suggested these may be the recent offspring of the Garlock and that the main Garlock fault zone is "dead in this area, though continuing active on the northeast in the Mojave Desert area.

Folding played a minor role in the structural development of the basin, though there are a number of small anticlines in the Tertiary rocks at the west edge of the valley. The predominance of nonmarine sediments makes it unlikely that any oil or gas will be found in commercial quantities.