A growing body of research emphasizes the importance of faculty support in shaping international students’ university experiences. However, the mechanisms linking faculty support to students’ sense of belonging remain underexplored. This study aimed to investigate the direct and indirect effects of faculty support on international students’ sense of belonging, focusing on the mediating roles of perceived campus climate and self-efficacy. Using a descriptive-correlational design, 512 international students (180 females, 332 males; M age = 25.28) enrolled in four public universities in Iran completed online questionnaires. Data were analyzed using Model 6 of Hayes' PROCESS macro in SPSS. Results indicated that Faculty support was significantly and positively associated with perceived campus climate, which in turn predicted students’ sense of belonging. However, neither the direct effect of faculty support on belonging nor the indirect effect through self-efficacy alone was significant. Although campus climate was positively related to self-efficacy, the serial mediation pathway through both mediators was not supported. The findings highlight the central role of a supportive campus climate in fostering international students’ belonging, whereas individual beliefs such as self-efficacy may play a less prominent role. The study underscores the importance of institutional and relational factors in enhancing the socio-emotional integration of international students in higher education.