Research consistently demonstrates that positive student-teacher relationships are fundamental to the healthy development of all students. However, we lack a Portuguese-validated measure of student-teacher relationships. In this article we present the adaptation procedures and the psychometric properties of a Portuguese version of the Student-Teacher Relationship Scale – Short Form (Pianta, 1992). Five hundred and thirty five teachers from 127 schools completed the STRS-SF. The results demonstrate that this adapted version of the STRS-SF has good psychometric properties, namely high reliability (α = .84 to .87) and expected construct validity, which were tested through exploratory and confirmatory factor analyses (χ2/df = 1.65, CFI = .96, GFI = .93, RMSEA = 0.05). This study also showed that the correlations of student-teacher relationship with students' demographic variables are consistent with the evidence in the literature about this construct. Finally, the study indicated that female teachers reported more closeness, t(530) = 4.06, p < .001 and better overall student-teacher relationships, t(530) = 4.90, p < .001. In the discussion, we analyze the implications of these results.