Spanish City Halls are making a great effort to develop citizen-targeted online services in an attempt to enhance their effectiveness and reduce expenses. Hence, citizens’ engagement is essential for the adoption of e-Government services. In this research, an extended Technology Acceptance Model (TAM) is developed to test citizen engagement towards online e-Government services from a sample of 307 citizens who used the benefits adviser tool within a Spanish City Hall. To achieve this goal, a structuring equation model is developed and tested to confirm the explanatory power of attitude towards a technology on citizen engagement. The results obtained suggest that the core constructs of TAM (perceived usefulness, ease of use and attitude) significantly affect users’ citizen engagement. This study also reveals a general support for attitude towards a technology as a determinant of citizen engagement in e-Government services. The implications of the findings are discussed and useful insights are provided on what policy to follow to establish the appropriate conditions to build citizens’ engagement intent.