This study was designed to investigate agility in adolescent changing voice males. Participants (N = 58), 11.5 to 15.9 years old, were from six Midwestern schools. The boys had varied experience in school and/or community choirs. Participants each were assigned to one of five stages of vocal maturation according to Cooksey's range stages, and to one of the two Cooper cambiata/baritone categories. These assignments were based on the participant's lowest terminal range pitch, and other observed tone quality factors. Each participant was recorded while singing a stepwise song pattern at increasing tempi, with and without lyrics. Judges later listened to the randomized recordings, and assigned agility scores for each participant at each of the six tempi, with and without lyrics. Agility scores were statistically analyzed with a 3-way ANOVA. Results were that (a) mean agility scores were increasingly higher from Cooksey stage one through stage five, (b) scores were significantly higher with lyrics than without lyrics, (c) there were significant differences related to tempo, with slower tempi associated with higher scores, and (d) there was a significantly positive relationship between mean agility scores and participants' years of choral experience. A summary of the findings was that: Boys in progressively later stages of voice change were judged to be increasingly more agile (singing a stepwise melisma) than in earlier stages, on average. Differences between cambiata and baritone were statistically significant for Cooper's range categories, but not for Cooksey's five stages of voice change. Agility was more accurate when lyrics were employed, than when "ahhh" was used to sing the stepwise exercises. Agility decreased as tempo increased. Agility correlated positively with years of choral experience.Implications for music educators include: If very fast passages exist in solo or choral repertoire, boys in the earlier midvoice Cooksey voice range stages (or Cooper's cambiata category) may have more difficulty than boys in later stages (baritone) of voice change. Songs using lyrics (consonant and vowel combinations) may be easier for changing voice boys to sing accurately, as compared to melismatic songs or passages using a single vowel.. As the tempo increases, changing voice students may have more difficulty with vocal agility. Choral repertoire such as European Baroque music may be more accessible as changing voice boys' choral experience increases.