Using daily diary methodology, 67 Mexican American adolescents completed measures assessing daily stressors experienced, specific coping strategies employed with reference to these stressors, and indices of psychological health over 5 consecutive days. With respect to coping usage, adolescents reported they most often used planning and least often used humor to cope with stress. Significant intraindividual and interindividual variability was found for each coping strategy and psychological health. When this variability was modeled, adolescents who reported using more direct problem solving, positive thinking, acceptance, and humor reported more positive affect. Adolescents who reported using more religious coping, distancing, and acceptance reported more negative affect. These findings indicate that intraethnic variability exists at the daily stressor level in Mexican American adolescents and that this variability in coping is predictive of daily psychological health. Discussion focuses on the developmental importance of flexible coping repertories in Mexican American adolescents and the (mal)adaptive nature of specific coping strategies. (Contains 2 tables and 2 notes.)