This study investigates the adoption of infak.id, the largest online infaq platform in Indonesia, by employing an integrated model based on Social Presence Theory and the Theory of Reasoned Action, extended to include technology adoption constructs. The research utilizes Structural Equation Modeling (SEM) to analyze relationships among the proposed variables, as SEM is effective in simultaneously estimating both direct and indirect effects within a single model. Data were collected through an online questionnaire distributed to purposively selected respondents across Indonesia, yielding a total of 389 valid responses. The results show that social presence (SP) and trust in fundraiser (TF) exert a significant positive influence on online infaq intention (INT). Although Muslim intrinsic religiosity (MR) does not directly influence INT, it positively affects attitudes toward online infaq (ATT), which in turn positively influences INT. Similarly, subjective norm (SN) positively influences ATT but does not directly affect INT. However, both MR and SN significantly impact INT through the mediating role of ATT. Furthermore, INT has a significant positive effect on technology adoption (TA). SP and TF also positively influence TA via the mediation of INT, whereas MR and SN do not exhibit significant indirect effects on TA through INT.