The goal of Head Start is to develop the cognitive and social-emotional skills of children from low-income backgrounds to prepare them to succeed in kindergarten and beyond. Houston Independent School District (HISD) collaborates with four federally-funded Head Start agencies: AVANCE, Gulf Coast Community Services Association (GCCSA), Harris County Department of Education, and Neighborhood Centers, Inc. (NCI). This evaluation examined the variation in the 2012-2013 kindergarten performance of students across the four Head Start programs as assessed by norm-referenced and criterion-referenced exams. Kindergarten performance between students who attended Head Start and were primarily economically disadvantaged (ED) versus their ED peers who were not enrolled in HISD prekindergarten or Head Start the previous year was also examined. There was little variation between Head Start programs on the norm-referenced reading and math subtests. There was almost none on the 2012-2013 Stanford. Kindergarten students who attended NCI performed slightly better than students who attended other programs with the largest gap being over Harris County, and students attending any Head Start program outperformed the district average for economically disadvantaged students on the Aprenda in both reading and math. Findings indicate that students who attended any local Head Start agency performed better on the Stanford reading and math subtests compared to their ED peers who did not attend HISD prekindergarten or Head Start; the relationship was even stronger after accounting for LEP status. Because HISD kindergarten students may have been dually enrolled in both Head Start and HISD prekindergarten or attended a Head Start standalone program, performance comparisons were also distinguished by these programs within each of the Head Start agencies. For the most part, Head Start students enrolled in the HISD partnership program outperformed their peers enrolled in the standalone programs on the Stanford and Aprenda reading and math subtests.