This exploratory study examined whether temperament, home environment, and family stress impact the amount of prosocial behavior displayed by pre-school age low-income children and examined how much of an impact each factor has. Each factor was explored in depth along sub-scale dimensions including, (1) self-regulatory temperament, negative reactive temperament, and positive reactive temperament, (2) physical environment, emotional environment, and learning environment, and (3) family stress due to financial difficulties, interpersonal tension, and child problems. This study applied a combination microsystem, mesosystem, exosystem, and macrosystem person-process-context model to explore the role these factors played. Subjects were 35 low-income pre-school age children who were enrolled in the Oregon Head Start Pre-kindergarten Program at Oregon State University. The Children's Behavior Questionnaire: Short Form, the Early Childhood Home Inventory, the Family Events Checklist, and the Modified Prosocial Behavior Questionnaire were used to obtain information about the relationship between the factors and prosocial behavior. Results indicated that the physical aspects of the home environment tended to positively contribute to the production of prosocial behavior and that family stress due to financial difficulties tended to negatively contribute to the production of prosocial behavior by low-income pre-school age children. This study did not establish that temperament was significantly related to prosocial behavior. These results have implications for those who are responsible for shaping children's behavior, such as teachers, parents, and home visitors by providing specific areas of focus for impacting behavior. These findings also support programs such as the Oregon Head Start Pre-kindergarten Program because it provides a venue through which impacts can be made. / Graduation date: 2000