A theory is presented of the angular momentum distribution of diatomic fragments ejected in the photodissociation of triatomic molecules. The theory is based on semi-classical dynamics and treats dissociation from an ensemble of nuclear configurations reflecting the zero-point oscillations of the parent molecule. The mean angular momentum of the diatomic is determined by the range parameter of the repulsive potential, while the width of its distribution is determined by the gradient parameters of the potential surface as expressed in the Franck-Condon spatial and angular coordinates. The odd moments of the asymmetrical distribution are related to the nonlinear part of the potential energy surface.