Short-term changes in vowel fundamental frequency (F
0
) immediately preceding (F
0
offset) and following (F
0
onset) production of voiceless obstruents were examined in groups of 4-year-olds, 8-year-olds, and 21-year-olds. Definitive patterns of laryngeal behavior were observed for each measure. F
0
was found to significantly lower at vowel offset across age groups, with no significant differences noted between groups, suggesting that F
0
offset is simply an acoustic consequence of producing a voiceless obstruent preceded by a vowel. The F
0
at vowel onset was high and significantly decreased thereafter. Age-related differences were identified for F
0
onset with 4-year-olds in that their F
0
rose to a lesser degree than that of adults. However, adult females demonstrated a greater change in both F
0
onset and F
0
offset behavior than adult males and children, suggesting that age-related differences in F
0
behavior are likely to be influenced by sex. The results are discussed with regard to the physiologic constraints of F
0
surrounding voiceless obstruent production in children and adults.
