This study examined age and gender differences in physical activity levels and various physical activity patterns of 11-14-year-old Turkish adolescents and also determined if these differ between genders. Six hundred and fifty girls and 666 boys between the ages of 11 and 14 years constituted the sample of this study. Participants self-reported physical activity levels and patterns were determined by a Weekly Activity Checklist. A 2 x 4 (Gender X Age) MANOVA revealed overall significant main effect of gender and age on the physical activity level of adolescents; however, gender X age interaction effect was not significant. The findings indicated an interaction effect was not significant. The findings indicated an age-related decline in physical activity level, an increase in participation in low activities, and a decrease in participation in moderate and vigorous activities in 11-14-year-old Turkish adolescents. In addition it was found that boys were more active than girls and participated more in moderate and vigorous activities.