According to self-determination theory, the satisfaction of the basic needs for autonomy, competence, and relatedness influences achievement emotions and situational interest. The present study investigated whether domain-specific explicit need strength moderated the impact of need satisfaction/dissatisfaction on the outcomes achievement emotions and situational interest. Self-report measures of domain specific need strength, perceived need satisfaction/dissatisfaction, achievement emotions (joy and boredom), and situational interest (catch-SI and hold-SI) were completed by 220 students attending 8th and 9th grade. Explicit need strength moderated the impact of perceived need satisfaction on hold-SI. Additionally, need strength moderated the impact of perceived need dissatisfaction on joy, boredom, and hold-SI. Nevertheless, need satisfaction had greater predictive power than need strength and the interaction effects appeared more consistently with the predictor perceived need dissatisfaction. Thus, need satisfaction seems to be the main explanatory variable for the outcomes. Conclusions are discussed. (Contains 5 tables and 2 figures.)