This study investigates the two frequency characteristics, F0 and F1F2, of the speech of Cantonese children, male and female, of nine age groups from 4 to 12. The F0 data on the Cantonese tones [55 33 22] from children show that (i) the patterns of the age-related decrease in F0 are similar between male and female children before age 12; (ii) at age 12, there is a large drop in F0 in male children, but not female children; and (iii) a significant difference in F0 between the two genders occurs only at age 12. The formant data on the five Cantonese vowels [i u ɛ ɔ a] show that the patterns of the overall drop in F1F2 as a function of age between male and female children are similar. The gender differences in F1F2 emerge at age 7 and increase significantly at age 12. Generally speaking, for Cantonese children, the gender-related difference lies mainly in F1F2 not F0, similar to the frequency data from English children reported in previous studies, which suggests a possible universal pattern of frequency development in children’s speech.