Abstarct: The present study aimed to investigate the effect of internal branding baxsed on an integrated community on brand commitment, considering the mediating roles of brand knowledge and social identity among employees of three departments—Human Resources, Marketing and Brand, and Sales and Support—at the central headquarters of Iran Mobile Communications Company (Hamrahe Aval). The research employed a descxriptive-correlational design, specifically structural equation modeling. The statistical population comprised 340 permanent employees from the three aforementioned departments, from which a sample of 181 respondents was selected using stratified random sampling baxsed on Morgan's table. Data were collected through validated standard questionnaires with confirmed reliability and validity. The findings confirmed all ten proposed hypotheses at a 95% confidence level. Accordingly, internal branding baxsed on an integrated community had both a direct positive effect on brand commitment and indirect effects through two separate mediating pathways: brand knowledge and social identity. Furthermore, social identity served as a full mediator in the relationship between internal branding and brand knowledge, while brand knowledge acted as a full mediator between social identity and brand commitment. In the discussion and interpretation of the results, a clear answer was provided to the main research question, revealing that the key to successful internal branding at Hamrahe Aval lies not merely in broadcasting brand slogans, but in fostering a sense of belonging and shared identity alongside deepening brand knowledge. This finding is significant because it demonstrates that investment in internal branding leads to genuine commitment only when employees first acquire in-depth knowledge of the brand and then perceive it as part of their own identity. Moreover, these results are consistent and aligned with the findings of previous researchers who have emphasized the mediating role of identity and knowledge in the internal branding process.