It is alarming that despite the numerous accrued benefits of physical activity participation, many young adults in tertiary institutions engage in inactive and sedentary lifestyles, which can be linked to many cases of morbidity and mortality. However, according to the self-determination theory (SDT), individuals have three basic psychological needs (BPNs) that are essential for healthy growth, development and well-being. The necessity to fulfill these BPN’s can stimulate and encourage young adults to engage in regular physical activity and enhance their well-being. Therefore, this study examined the role of BPN’s in predicting physical activity participation among young adults in Nigerian private university. A total of 735 students, comprising 408 males (55.5%) and 327 females (44.5%), with ages ranging from 16 to 35 years (mean = 22.8; SD = 5.42), were randomly selected from a private university in the South-west, of Nigeria. The Basic Psychological Needs in Exercise Scale (BPNES) and the International Physical Activity Questionnaire–Short Form (IPAQ-SF) were used to collect data. Data analysis was conducted using descriptive statistics, correlation and multiple linear regression analysis. The results of the study showed that the BPN’s of autonomy (r =0.233, p<0.05); competence (r =0.188, p < 0.05), and relatedness (r = 0.477, p<0.05) positively correlated with physical activity participation. Additionally, the results found that 25% had low, 57.1% had moderate and 17.8% had high levels of physical activity participation among the participants. There was a significant gender difference between males and females’ in their levels of participation in physical activity (t =2.866, p < 0.05), with males reporting higher mean scores than their female counterpart. Regression analysis showed that BPN’s predicted physical activity participation among young adults (F (3,731) = 73.968, p < 0.05) with 23% of its variance accounted for by the independent variables. Furthermore, autonomy (ß = 0.071, t = 1.970, p < 0.05) and relatedness (ß = 0.478, t =12.589, p < 0.05) were predictors of physical activity participation with relatedness being reported as the most potent predictor. These findings provide an insight into focus the importance of satisfying the relatedness and autonomy aspects of BPN’s in young adults. Developing interventions that target these identified indices can promote continuous and regular participation in physical activity. Keywords: basic psychological needs, relatedness, autonomy, physical activity, young adults