This paper describes the socio-psychological issues that hinder the holistic usage of ERP system among sampled Malaysian SME’s that were the vendors through government outsourced projects. Five hundred questionnaires were sent to the pre-identified SMEs in Selangor through e-mail, 251 questionnaires were returned and only 110 were taken for data analysis, representing 44% of the response rate. The study found that the perceived benefits and social influence have positive significant relationship with the ERP system usage. The social influence has the strongest effect towards the ERP system usage among SMEs in Selangor. The system complexity does not influence the relationship between socio-psychological factors and ERP system usage among SMEs in Selangor. This study provides insight for the management of SMEs and the service providers on the factors influencing the ERP system usage. It contributes to the breadth of knowledge of the ERP system in SMEs from the perspective of a developing nation since the SMEs play an important role in the nation’s economy.