We conducted a meta-analysis on the effectiveness of cooperative and collaborative learning to support enhanced literacy outcomes. Interventions considered were provided in regular education settings (i.e., not pull-out instruction) with students from Grades 2 through 12. Reviewing more than 30 years of literacy research, we located 18 intervention studies with 29 study cohorts. Included studies primarily used standardized assessments to report on students' reading, vocabulary, or comprehension achievement, which we analyzed separately. Overall, students had significantly higher literacy achievement scores when instructional interventions utilized cooperative and collaborative activity structures. The overall weighted mean effect sizes ranged from 0.16 to 0.22 ("p" < 0.01) with more than 94% of the point estimates being positive. Because cooperative or collaborative learning was always one of multiple intervention components, it was impossible to estimate the unique, added effects of cooperative/collaborative learning. Although the small number of eligible studies precludes any claims about the effectiveness of specific forms of grouping and the circumstances under which programs have more impact, our findings suggest that cooperative and collaborative grouping was a core component of effective literacy interventions, particularly at the elementary level.