Decades of research suggest that both Head Start and public pre-kindergarten (pre-k) programs boost low-income preschoolers' kindergarten skills. What is not yet well understood is whether there are relative advantages of transitioning from Head Start after 1 year into a school-based public pre-k program for the year immediately before kindergarten for children's developing cognitive and self-regulation skills. This is an important question, because in many communities Head Start and school-based pre-k programs provide competing early education options for low-income 4-year-olds, leaving policymakers, educators, and parents wondering which pathway best promotes the mix of skills predictive of success in elementary school. Only one study--conducted prior to significant recent demographic and policy changes affecting early education and focused exclusively on cognitive outcomes--has addressed this question. We extend that work with contemporary data on 362 low-income children to assess the relative advantages for both kindergarten cognitive and self-regulatory skills of 2 years of Head Start before kindergarten versus transitioning from Head Start to school-based pre-k at age 4. The child sample was evenly split by gender and diverse in race/ethnicity (50% Hispanic/Latinx; 36% Black; 7% White). Results showed that children who transitioned after 1 year of Head Start to school-based pre-k at age 4 showed marginally higher kindergarten literacy (d = 0.13) and significantly greater math (d = 0.18) skills than children who remained in Head Start for a second year, but there were no significant differences in kindergarten self-regulatory skills. Implications for contemporary, pressing policy issues are discussed. [The Tulsa SEED Study Team contributed to the writing of this article.]