In this study, we examined whether socio-motivational relationships, such as student-student relationships (SSR) and teacher-student relationships (TSR), as well as peers as positive motivators (PPM) and teachers as positive motivators (TPM), would mediate the association of both perceived stress and neuroticism with test anxiety in 1,088 German students from grades seven and eight. Results from structural equation modeling revealed that a high quality of SSR mediated the relationship between neuroticism and test anxiety, which was not the case for TSR. Furthermore, both PPM and TPM acted as mediators in all hypothesized associations. Interestingly, although a high quality of SSR mitigated feelings of test anxiety, PPM and TPM intensified test anxiety in neurotic students. The role of social relationships as protective factors as well as risk factors is discussed, as are the implications of the findings for educators, school psychologists, and teachers.