This research aimed at studying the influence of basic psychological needs on academic achievement taking into account the meditational effects of identity styles. 330 students (166 males and 164 females) were selected using cluster sampling and answered to the basic psychological needs (La Guardia, et al. 2000) and identity styles (Berzonsky, 1992) questionnaires. Path analysis revealed that basic psychological needs exerted a direct, significant influence upon identity styles and academic achievement. In addition, basic psychological needs exerted an indirect one upon students’ academic achievement through the mediation of identity styles. Results indicated informational style had a positive direct influence upon academic achievement, while normal style influenced academic achievement in a negative correlation (p < 0.05). The direct influence of Diffuse / avoidant style on academic achievement was not significant. In general, this study emphasized the influences of basic psychological needs and identity styles on academic achievement.