Research and theory have highlighted the influence of self-evaluations on achievement behaviors, cognitions, and affective responses. Nevertheless, the focus has primarily been on level of self-evaluations (i.e., high or low). One individual difference factor receiving increasing attention is the degree to which individuals exhibit short-term fluctuations in their self-evalu~tions (i.e., intraindividual variability). Research in developmental and social psychology has shown that intraindividual variability of global self-esteem is related to motivational and affective responses above and beyond level of self-esteem. The goal of this study was to extend the literature on self-evaluations by examining intraindividual variability of global and physical self-evaluations (i.e., global self-worth, physical self-worth, perceived physical competence). Specifically, the study examined: (a) the prevalence of intraindividual variability of global and physical selfevaluations; (b) the independent and combined influence of level and intraindividual variability of self-evaluations on motivation and affect toward physical activity; and, (c) the relationship between social sources of evaluative information and intraindividual variability. Middle school students (N = 167) ranging in age from 12-15 years (M = 13.48 years, SD = .56) completed questionnaires each day that they were in physical education class for 3 weeks (i.e., 6 occasions). Results revealed that the majority of the boys and girls exhibited fluctuations in their self-evaluations over the 3 weeks. Level of self-evaluations was the critical predictor of affect and intrinsic motivation in most analyses; however, stability of self-evaluations did make varying contributions to the prediction of intrinsic motivation and affect, but not effort and persistence. The influence ·of intraindividual variability was particularly salient for adolescents with higher levels of iii global self-worth. Students with higher but relatively less stable global self-worth exhibited lower intrinsic motivation and affect than students with higher but stable global self-evaluations. Nonsignificant relationships were found between intraindividual variability and the importance that students' placed on social sources of evaluative information. Overall, results indicated that intraindividual variability of global and physical self-evaluations should be considered along with level to gain a more complete understanding of adolescents' sport and physical activity experiences.IV ACKNOWLEDGEMENTS