The concept of stereotype, an important topics of social psychology is closely related to prejudice and discrimination. Stereotypes may drag people into generalization and failure in judgements in addition to many unwanted behavioral outcomes. The first section of the article deals with the definition of the concept of stereotype and ascertains the motives of individuals who intend acting in accordance with stereotypes, followed by offering various solutions to this very problem. The second section points out the effect of stereotypes on interpretation of the social judgement and the social cognition while the third section dwells on how stereotypes can be changed. This study, which presents a summary of the researches about the stereotype and the social judgement is of importance in terms of indicating how stereotypes turn into prejudices and how they eventually cause discrimination.