A wind turbine blade has a blade body and a leading edge fairing. The blade body has a root, a tip, and a longitudinal direction extending between the root and the tip. The 5 blade body also has a channel extending in the longitudinal direction. The leading edge fairing has a projection extending into the channel and extending in the longitudinal direction so as to be received in the channel. Also, a leading edge fairing for attachment to a blade body of a wind turbine blade; a method of fitting a leading edge fairing to a wind turbine blade; and a kit of parts with a number of the leading edge fairings.