With the rise of digital platforms, the tourism industry has also developed with the emergence of various websites or applications that make it easy for users to access information and book services in the tourism sector. This research aims to analyze the effect of e-service quality (e-SQ) on cross-buying intention (CBI) and whether e-customer relationship management (e-CRM) plays a role in strengthening this connection as a mediating variable in online travel agents (OTAs). Using a quantitative research approach and SEM-PLS for analysis, the samples were collected by convenience sampling via questionnaires to OTA users who actively use online services. Interestingly, the findings reveal that there was no significant impact between e-SQ and CBI, however e-CRM acts as a mediator that strengthens the connection between e-SQ and CBI. The findings of this study offer valuable insight for OTA companies into market opportunities and set strategies for increasing customer satisfaction. By optimizing personalized websites or applications, OTAs can encourage repeat purchases and cross-buying behavior.