Perception of voice cues, voice pitch (F0) and vocal-tract length (VTL), is important for recognizing speakers. Its investigation in children with hearing devices could be challenging due to the combined effects of cognitive development and distortions induced by hearing loss. We measured voice cue just-noticeable- differences (JNDs) in school-age children with hearing aids, cochlear implants, or typical hearing. Children with hearing aids had, overall, larger voice cue JNDs (less sensitive) than the control group, but this effect was mostly confined to younger ages. Individual data showed relatively large overlap between the JNDs of typically-hearing children and those using hearing aids. For the few children with very large JNDs, the degree of hearing loss or aided thresholds did not seem determining factors. Children with cochlear implants in general had larger voice cue JNDs than the control group, but these seemed to overlap more with JNDs of their own controls than those of implanted adults’ overlap with their own controls. In all children, general developmental effects were seen, although these differed between F0 and VTL. Overall, results confirm that early use of hearing devices can provide benefits in voice perception, and with continued use of the devices, this ability may develop further.