The purpose of this research was to examine the effects of Families and Schools Together Program (FAST) on social, general and parenting self-efficacy of first graders’ parents in Tabriz. This quasi-experimental study had a pretest-posttest control group design. The statistical population of the study consisted of the parents of all first graders enrolled in public schools in Tabriz in 2018-19 school year. For the purpose of sampling, purposive sampling method was utilized and 40 families were selected. These families were assigned to an experimental (20 families) and a control group (20 families). During the study, the experimental group took part in the Families and Schools Together Program for eight 2.5-hour sessions and the control group did not receive any intervention. The analysis of covariance showed that the experimental group’s social, general and parenting self-efficacy increased dramatically (p<0.05). Hence, it can be concluded that participating in Families and Schools Together Program has the potential to increase social, general and parenting self-efficacy.