A liquid supply apparatus configured to supply a liquid to a printing unit, comprising a tray on which a flexible retaining container that retains a liquid is configured to be placed, and a tray holder configured to hold the tray so as to allow insertion of the tray in a first direction, wherein the retaining container includes a supply port configured to supply a liquid to the printing unit and an inlet coupled to the supply port and configured to take in a liquid into the retaining container, and the tray is provided with a concave shape overlapping the inlet from a viewpoint in an up-down direction in a state in which the tray is inserted in the tray holder.