The present investigation aims to analyze the effect of motivation on students' causal attributions to choose or abandon chemistry when it first becomes optional in the secondary education curriculum in Spain. Attributions to the effect of the family and to the teacher and classroom methodology were found to be common predictors of the choice to all the students in the sample. However, our analyses point to a significant effect of the students' motivation in other types of attributions. In the case of at-risk of abandonment students, specific causal attributions to the effect of friends and to the subject's relationship with mathematics were found. On the other hand, the effect of media was a significant predictor only in the case of highly-motivated students. Our study provides several suggestions for teachers, schools, and administrations to design counseling strategies to help students make the right choices.