Electronic Government Procurement (e-GP) has been adopted by many governments worldwide due to its numerous benefits. Similarly, the Government of Sri Lanka is in the initial stages of implementing an e-GP system for the public sector, known as PROMISe, Sri Lanka. However, the absence of a context-specific framework presents a challenge in understanding adoption factors. Therefore, this study aims to develop a conceptual model to identify the key determinants influencing the adoption intention of public sector employees toward the e-GP system in Sri Lanka. The study employed an iterative conceptual methodology for the model development process. It guided the model development by drawing on high-quality literature, widely accepted theoretical models, and logical reasoning. The Technology Acceptance Model (TAM) and the Unified Theory of Acceptance and Use of Technology (UTAUT) serve as the foundation for the proposed model. The study adopts several key constructs from these frameworks: perceived usefulness (PU), perceived ease of use (PEU), facilitating conditions (FC), and social influence (SI). Additionally, the influences of digital literacy and the type of organization have been incorporated into the model to reflect context-specific influences for Sri Lanka. The expected associations between all elements in the model have been clearly elaborated in the paper. Additionally, the dimensions for operationalization and the measurement scales for each construct have also been illustrated. The model proposed in this paper can be used by future researchers to validate it with empirical data from the Sri Lankan public sector.