Abstract: A gasket (18) for a valve (12) of an internal combustion engine (1) includes a supporting element (26) having a tubular conformation according to an axis (B), and an elastically deformable element (25) adapted to be arranged between the valve (12) and the supporting element (26). The supporting element (26) includes a first portion (42) extending transversally to the axis (B) and adapted to receive an action with component parallel to the axis (B) itself to facilitate the assembly of the gasket (18) on the valve (12), and a second portion (41) elongated towards the axis (B) from the first portion (42) and in turn including at least one segment (45) having an increasing radial dimension towards the first portion (42) itself (46) so as to reduce the volume of the elastically deformable element (25).