A combustor assembly for a gas turbine engine is provided. The combustor assembly includes a liner at least partially defining a combustion chamber and extending between an aft end a forward end generally along an axial direction. The combustor assembly also includes an annular dome including an enclosed surface defining a slot for receipt of the forward end of the liner. A cap is positioned at the forward end of the liner and at least partially positioned within the slot defined by the enclosed surface of the annular dome. The cap includes a surface configured to contact at least one of the enclosed surface of the annular dome and the forward end of the liner. Such a configuration may form a substantially airtight seal between the forward end of the liner and the annular dome despite a relative thermal expansion between the components.