In compliance with the Texas Education Code § 29.153, the Houston Independent School District (HISD) has provided free prekindergarten classes for eligible Houston area four-year old students since the 1985-1986 academic year. The program curriculum focuses on beginning literacy, numeracy, social emotional development as well as supporting the individual linguistic and cultural needs of the children served. The prekindergarten program curriculum forms the basis of children's future academic success. The purpose of this evaluation is to examine the extent that students benefit from attending HISD prekindergarten. To determine the academic benefits of HISD prekindergarten programs, the academic performance of students who attended HISD prekindergarten programs was compared to students who were not enrolled in HISD prekindergarten programs in the previous year. The report addresses the following issues: (1) The performance of HISD and Non-HISD prekindergarten students on the 2014-2015 kindergarten IOWA and Logramos English Language Arts (ELA) and mathematics subtests; (2) The effects of HISD prekindergarten programs on students' ELA performance by student subgroups; and (3) The effects of HISD prekindergarten programs on students' mathematics performance by student subgroups. This evaluation also examined prekindergarten program enrollment trends and the proportion of kindergarten students enrolled in HISD and Non-HISD prekindergarten programs from 2006-2007 to 2014-2015.