Previous research has demonstrated early-emerging gender associations with musical instruments. We investigated whether pitch, loudness and size affect gender-instrument associations in older (M[subscript age] = 9.37 years, N = 57) and younger (M[subscript age] = 7.73 years, N = 63) children (approximately even gender split, mostly North American), as well as American undergraduates (M[subscript age] = 19.57 years, N = 50). Participants selected whether a girl or boy character should play fictional instruments with different pitch (high/low), volume (loud/soft) and size (large/small). Children were more likely to select boy characters for low- than high-pitched instruments (60% vs. 44%), as were adult undergraduates (79% vs. 54%). Older boys were also more likely to select boy characters for loud than soft instruments (68% vs. 52%). Size had no effect for any group. Results suggest pitch and loudness impact gender-instrument associations, and that gender associations are not restricted to gender-instrument pairings children have former experience with.