An apparatus (60) is provided for forming a trailing edge (52) of a wind turbine blade having first and second shells (40, 42). The first and second shells define a gap therebetween, and the apparatus has a first mold component (62) that is adapted to form the first or second shell, and an engaging element (77). The engaging element is configured to securely support a trailing edge component to be coupled to the first and second shells. The engaging element is coupled to the first mold component. The apparatus may additionally include a second mold component (64) that is adapted to form the other of the first or second shells and which is coupled to the first mold component. In this embodiment, the first and second mold components have a closed position in which the first and second shells are closed over one another so as to define a generally closed profile of the wind turbine blade.