The coach-athlete relationship and coach communication have received significant attention, as they relate to athlete performance variables; however, the coach alone does not shape an athlete's experiences. Research has indicated the importance of the parent/guardian's role in athlete development and suggests parent/guardian communication may also have implications for athlete performance outcomes. Of such performance variables, self-efficacy has been demonstrated to have a consistent positive and moderate relationship with sport performance. The purpose of this study was to examine the effects of parent/guardian communication on student-athlete self-efficacy. Student-athlete participants (n = 290) provided self-reports of self-efficacy, family communication patterns, and the frequency-of-use and effectiveness of the efficacy-enhancing techniques employed by parent(s)/guardian(s). Results revealed a significant negative relationship between conformity-oriented communication and student-athlete self-efficacy. Regarding efficacy-enhancing techniques, the most frequently used and effective were reported as encouraging positive talk, parent/guardian acting confident themselves, and helping the student-athlete imagine optimal sport performance. Practical implications for parent(s)/guardian(s) are provided that can help inform parenting education efforts to better clarify the role of the parent/guardian in optimal student-athlete development and performance. The study's limitation and directions for future research are discussed.