A fuel injector for an internal combustion engine is disclosed. The fuel injector is installable in a cylinder head bore of a cylinder head of the engine and has a body region arranged to be received within the cylinder head bore, and a head region arranged to extend outside the cylinder head bore to protrude from the cylinder head when the injector is installed in the cylinder head bore. The injector includes a first valve needle arranged to control the injection of a gaseous fuel from a first outlet, a second valve needle arranged to control the injection of a liquid fuel from a second outlet, a gaseous fuel inlet for admitting the gaseous fuel to the injector, and a liquid fuel inlet port for admitting the liquid fuel to the injector. The gaseous fuel inlet is disposed in the body region of the injector, and the liquid fuel inlet port is disposed in the head region of the injector. The injector can also include an internal accumulator volume so that an external fuel rail is not necessary.