This study examined the differential impact of an educational intervention on high school students' career maturity based on gender. Dimensions of career maturity investigated include congruence, career certainty, career indecision, career decision-making self-efficacy and career exploration. Females were found to increase significantly in congruence and decrease significantly in career indecision as a result of the intervention. Males' career decision-making self-efficacy was positively and significantly affected by the intervention, and the extent of their career engagement was found to have been significantly and negatively affected. These gender differences suggest the development of career maturation occurs differentially for males and females.