The disclosed flexible facial interface assemblies for head-mounted display systems may include a rigid support frame element and a flexible facial interface frame element. The rigid support frame element may be shaped and configured to physically support a display of a head-mounted display system in front of a user's eyes when the facial interface assembly is worn by the user. The flexible facial interface frame element may be configured to flex to conform to the user's facial features when the facial interface assembly is worn by the user. An outer periphery of the flexible facial interface frame element may be independently movable relative to an outer periphery of the rigid support frame element. Various other systems and methods are also disclosed.