The Self-Determination Inventory: Student Report (SDI:SR) is a newly developed measure of self-determination. The purpose of this study was to explore of personal factors, namely age and gender on scores on the SDI:SR. Separate multigroup confirmatory analyses were conducted for age cohorts (13- to 15-, 16- to 18-, and 19- to 22-year-olds) and for females and males to establish measurement invariance and explore latent differences. Findings suggest the same set of items can be used in all groups. No latent differences were found for females and males, but expected age-related differences (e.g., younger participants showed lower levels of self-determination) were established. Finally, the degree to which age and gender influenced scores for 12 groups created by crossing disability status and race/ethnicity was examined. Findings suggest that females with no disability or learning disabilities generally score lower in overall self-determination than males and general positive impact of age on scores across disability by race/ethnicity groups. Implications for research and practice are discussed.