The current study examined physical activity, free time motivation, and perceptions of physical activity of middle school children. The purpose was to describe why some children are attracted to or avoid physical activity. There were three main research aims for this study. First, free-time motivation using a self-determination based Free Time Motivation Scale was studied to determine the current status in a group of middle school children (N = 252). Second, participants were identified to wear activity monitors so that free time motivation and physical activity relationships could be determined (n = 127). Finally, influences on free time physical activity decision making was studied using a semi-structured interview format. Results from the 56 phase III participants indicated that external motivational factors were correlated to minutes of Moderate to Vigorous Physical Activity (MVPA) per day (r = .31, p < .05). A school (private versus public) X gender comparison was run on the five motivational scale scores and MVPA of participants. This 2 X 2 multivariate analysis of variance indicated that males had higher activity levels than females, F(1, 55) = 11.92, p > .001, Eta2 = 19, with no differences noted between public and private school participants (p > .01). Main effects were not found in motivational subscales for gender or school setting. Qualitative interviews resulted in thematic descriptions related to how children perceive fitness and health. Results support that middle school participants tended to cite body size and weight as factors that describe both fit and healthy individuals. Further, a continuum of five influences emerged that are theorized to impact free time decision making related to physical activity, including rules, followed by fun, success, dedication, and finally passion. Keyword(s): middle school issues, research