The study aimed to test the psychometric properties of a Portuguese adaptation of the "Adolescent Students' Basic Psychological Needs at School Scale" (ASBPNSS). For this, we used data from a sample of eighth graders (N = 1648; M[[subscript age] = 14.1 years; 46.9% girls) from Portugal. Cronbach alpha and omega coefficients showed the ASBPNSS subscales--autonomy, relatedness, and competence--were reliable. Confirmatory factor analysis (CFA) showed the hypothesized three-factor model fit the data well. Multi-group CFAs showed the ASBPNSS had scalar invariance across gender and students from different socioeconomic backgrounds. Finally, need satisfaction in school was positively correlated with positive affect and life satisfaction and negatively correlated with negative affect. These findings support the theoretical assumptions of Basic Psychological Needs Theory (BPNT), and particularly the assumption that basic needs are universally applicable. We conclude the ASBPNSS is a reliable and valid measure of basic need satisfaction at school in Portuguese adolescents.