Self-objectification (i.e., valuing the body primarily for its attractiveness to others) is negatively related to physical health, including physical activity (PA) attitudes and behaviors. Given the low levels of PA among middle-aged adults in the US, self-objectification may be a novel correlate of PA in this population. The present study examined self-objectification and PA variables in a cross-sectional Western U.S. community sample of women (n = 215) and men (n = 134), aged 45-64, including gender as a moderator of these relations. Data were collected via survey, including measures of self-objectification, PA enjoyment, PA perceived benefits and barriers, and self-reported levels of PA. Women and men in our sample did not differ in levels of self-objectification. Results of regression analyses indicated that self-objectification predicted less PA enjoyment. In addition, men higher in self-objectification reported higher levels of PA. The findings implicate self-objectification as a potentially novel determinant of PA attitudes and behaviors in middle-aged adults.