This paper examines the process of clique formation among company employees using the agent-based simulation model. With the reciprocity principle and the resource exchange theory, the model exhibits how interactions lead to interpersonal connections, which gradually form small groups whose members provide mutual support but exclude others from getting in. These small groups are eventually shaped into cliques. For the present study, two work-environment variables and one organizational-culture variable were selected to examine the factors that might influence clique formation. The resulting curve showed that heavy work load beyond one’s resources and inequality in work assignment could accelerate the formation of cliques and their further demarcations; on the other hand, very light work load and perfect equality in work assignment tended to reduce interpersonal interactions, hence employee isolation.