This chapter outlines the definitions and dynamics of racism, emphasizing that it is a form of prejudice supported by societal norms and institutional practices, particularly affecting people of color in the United States. It explores the psychological mechanisms behind individual racism, such as in-group behavior and categorical thinking, while also highlighting the damaging effects of microaggressions and implicit biases. Furthermore, the chapter stresses the importance of awareness among human service providers regarding their own prejudices and the systemic inequalities faced by clients of color.