Abstract: A tray attachment for a chair with at least one armrest (AR) of a substantially inverted-U or inverted L-shaped cross-section having a top portion (TP) and at least one lateral flange portion (FP), the attachment including a tray member (2) having an upper side and an underside, at least one arm (10), fixedly attached to or integral with the tray member (2) and extending in a direction substantially perpendicular to the plane of the tray member, the free end of the arm being configured to form a hinge (28,30); a clamping member (14) including a clamping arm (34) joined to a clamping jaw (36) and being articulated to the hinge, and a detent (18) mounted on a post (16) positioned on the underside of the tray member in a spaced-apart relationship with the arm.