Purpose: This study investigated the masticatory efficiency and ability in girls with normal occlusion and Class II malocclusion. Furthermore, it investigated the association between masticatory efficiency and ability on one hand and signs and symptoms of temporomandibular disorders (TMD) on the other hand. Materials and Methods: A total of 183 girls, aged 11 to 15 years, were included in this study. Sixty subjects had normal occlusion and 123 subjects had Class II malocclusion. The examination included registration of signs and symptoms of TMD. Masticatory efficiency was evaluated with a masticatory efficiency test, while masticatory ability was self-assessed on a visual analog scale. Results: Subjects with normal occlusion presented statistically significantly better masticatory effiency and ability than subjects with Class II malocclusion. Thirty percent of the variation in masticatory efficiency was explained in a multiple regression analysis. Few occlusal contacts and a large overjet predicted a reduced masticatory efficiency. Subjects who reported frequent temporomandibular joint clicking and subjects who estimated their overall symptoms of TMD as moderate or severe also had reduced masticatory efficiency. Conclusion: The authors concluded that masticatory efficiency and ability were partly dependent on the occlusion and that symptoms of TMD influenced the masticatory efficiency and ability.