This study investigated how age and gender shape Chinese adolescents' explicit and implicit attitudes toward adult speakers with gender-nonconforming voices. A total of 214 participants (Nfemale = 105), aged 9-18, were categorized into three age groups: younger (9-12), middle (13-15), and older adolescents (16-18). Explicit attitudes were measured using a five-item questionnaire assessing social preferences (e.g., friendship), while implicit attitudes were measured using two Implicit Association Tests (IATs). Across all age groups, participants showed more negative explicit and implicit attitudes toward gender-nonconforming voices compared to gender-conforming voices. Gender differences emerged for both speakers and listeners. Younger and middle adolescents exhibited greater prejudice toward gender-nonconforming female voices than male voices. Boys generally displayed more negative attitudes than girls, particularly in older adolescents. Regarding age differences, older girls expressed less explicit prejudice toward gender-nonconforming voices than younger girls, whereas boys' explicit attitudes remained relatively stable. In contrast, implicit bias against gender-nonconforming female voices increased with age, particularly among older adolescents. These findings highlight developmental and gender-related variations in responses to gender nonconformity, and underscore the divergence between implicit and explicit biases during adolescence.