Purpose: This study was designed primarily to determine if a critical-thinking task involving fables would elicit greater syntactic complexity than a conversational task in adolescents. Another purpose was to determine how well adolescents understand critical-thinking questions about fables. Method: Forty adolescents (N = 20 boys and 20 girls; mean age = 14 years) with typical language development answered critical-thinking questions about the deeper meanings of fables. They also participated in a standard conversational task. The syntactic complexity of their responses during the speaking tasks was analyzed for mean length of communication unit (MLCU) and clausal density (CD). Results: Both measures of syntactic complexity, MLCU and CD, were substantially greater during the critical-thinking task compared with the conversational task. It was also found that the adolescents understood the questions quite well, earning a mean accuracy score of 80%. Conclusions: The critical-thinking task has potential for use as a new type of language-sampling tool to examine language production and comprehension in adolescents.