Multisensory integration has seldom been examined in adolescents. Thus, performances on an audiovisual discrimination task were compared between 19 adolescents (M=15:00 SD=0:04 years), 20 primary school-aged children (M=11:04 years, SD=0:05 years) and 22 young adults (M=26:02 years, SD=2:07 years) in quiet and in auditory, visual and audiovisual noise conditions. Stimuli comprised domestic animal exemplars. Motor reaction times (MRTs) and accuracy were recorded. Adolescents had equivalent false positive error rates but significantly lower false negative error rates than children. Children and adolescents had higher error rates than adults. MRTs differed significantly between all groups, being fastest for adults and slowest for children. Adults and children showed facilitation in all noise conditions, while adolescents showed equivalent, faster MRTs to visual and audiovisual than auditory targets in auditory noise. Coactivation was evident in all noise conditions for adults (probabilities of .05-.65 in quiet and auditory noise, .15-.65 in visual noise and .15-.25 in audiovisual noise) but was limited to quiet and auditory noise conditions for children (probabilities of .05-.15) and adolescents (probabilities .05-.65 and .15-.45, respectively). The results indicate that adult-like levels of multisensory integration develop by adolescence in quiet conditions but remain immature in unisensory and audiovisual noise.