Recent research has shown that undergraduate students who experience both clinical and subclinical attention-deficit/hyperactivity disorder (ADHD) struggle academically. Furthermore, these students have cited academic amotivation as a factor in their academic difficulties. Self-determination theory (SDT) posits that a lack of motivation--known as amotivation--may be the result of the frustration of the basic psychological needs--autonomy, competence, and relatedness. For this reason, the current study examined whether basic psychological need frustration mediated the relationship between ADHD symptomatology and academic amotivation. A sample of undergraduate students completed an online questionnaire about their university experience. Data were analyzed using a mediational structural equation model. Results suggested significant relationships between all of the variables. Moreover, basic psychological need frustration fully mediated the relationship between ADHD symptomatology and academic amotivation. These results demonstrate the importance of fulfilling the basic psychological needs of undergraduate students experiencing ADHD symptomatology, as it may increase their academic motivation, and, subsequently, reduce their academic difficulties.