This study examines how perceived utility, ease of use, knowledge, awareness, and trust in government affect digital taxation information system utilization in Indonesia. SEM PLS analysis and a poplite media poll of 130 taxpayers were utilized to quantify the study. Knowledge and trust in government increase system utilization. However, usefulness, ease of use, and awareness do not affect system use. These data support the Theory of Planned Behavior (TPB) that cognitive and institutional variables drive technology adoption, not functionality. This study supports TPB and TAM theories by indicating that institutional trust and cognitive capacity are more important than technical perception in technology adoption in underdeveloped nations like Indonesia. TPB and TAM theories should be included in public sector digitization, according to the study. According to the TPB principles, the government must first promote tax literacy and policy transparency to increase taxpayer awareness and trust. Second, the insignificance of TAM principles suggests that system design must balance technical complexity with institutionally influenced user wants.