Hornsby Maintenance Depot is a train depot in the northern Sydney suburb of Asquith, New South Wales, Australia, that primarily services the Sydney Trains fleet.

It is located to the north of Hornsby station, a major interchange on the Sydney Trains network, and alongside the Main North line.

[1] The depot features nine roads under the main shed (numbered 1–9), five outdoor roads (numbered 11–15), two of which (11 and 12) are elevated, a train washing facility (16 road) and several short outdoor storage sidings.

The track layout is such that trains can only enter from the south.

It is a stabling location for A (Waratah) sets, T (Tangara) sets and H (OSCAR) sets and crew depot, for services on the Central Coast, Northern, North Shore, and Western lines.