The goal of Head Start is to develop the cognitive and social-emotional skills of children from low-income families 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 (HCDE), and Neighborhood Centers, Inc. (NCI). The purpose of this evaluation was to examine the effect of the Head Start programs on student performance using the 2013-2014 kindergarten Stanford and Aprenda mathematics and reading tests and the 2013-2014 third grade STAAR reading and mathematics tests. The most notable findings of this evaluation were: a) the performance of students who were dually-enrolled in HISD and one of the four Head Start programs outperformed students who were enrolled in standalone programs on the 2013-2014 kindergarten Stanford reading and mathematics subtests; b) there was little variation between Head Start programs on the 2013-2014 kindergarten Stanford and Aprenda reading and mathematics subtests; c) the longitudinal data analysis results show that among the four Head Start agencies, AVANCE had the highest percentage of student who met the 2014 STAAR Level II: Satisfactory (Phase-In 1) standard, and obtained the highest mean scale scores on the 2013-2014 STAAR reading and mathematics tests.