This research, based on the theoretical frameworks of Positive Psychology and Mathematics Teaching, aimed to investigate the possible relationships between Positive and Negative Affectivities and School Performance in Mathematics. To achieve this objective, a survey was used to collect data on affectivity in a sample of students from technical courses integrated into high school and collected data on school performance in Mathematics through the semester grades of these same students. With these data in hand, we proceeded to data analysis. This analysis was carried out using Pearson's Correlation Coefficient (r), which resulted in evidence of the existence of a moderate correlation between Positive Affectivities and School Performance in Mathematics, as well as evidence of the existence of a weak correlation, but between Negative Affectivities and School Performance in Mathematics. Thus, it was concluded by the statistical confirmation of the relationship between Positive and Negative Affectivities and School Performance in Mathematics. This research also advised parsimony in the generalization of its conclusions, since there was a limitation linked to the use of the convenience sampling technique and, in addition, suggested that future studies explore other concepts belonging to the field of Positive Psychology and that others be investigated types of relationship, in addition to correlation, since there is the possibility of seeking evidence on cause/effect, mediation and moderation relationships related to Mathematics Teaching constructs.