In compliance with the Texas Education Code, the Houston Independent School District (HISD) has provided free prekindergarten classes for eligible Houston area four-year old students since the 1985-1986 scholastic year. The program curriculum focuses on beginning literacy, numeracy, and socio-emotional development, supporting the individual linguistic and cultural needs of the children served. The purpose of this evaluation is to examine the extent that students' benefit from attending HISD prekindergarten. To determine the academic benefits of prekindergarten, the academic performance of students who attended HISD prekindergarten were compared to students who were not enrolled in prekindergarten the previous year after controlling for various demographic characteristics. The current report also examines prekindergarten program enrollment trends and the proportion of kindergarten students enrolled in HISD prekindergarten from 2006-2007 to 2012-2013. Findings from the evaluation are consistent with previous evaluations (Corkin, 2012) and suggest that the effects of HISD prekindergarten on students' kindergarten Stanford reading and math performance are stronger for students who are economically disadvantaged. In other words, it seems that students who are economically-disadvantaged receive greater benefits from attending prekindergarten compared to their more affluent peers based on the greater gains made by economically-disadvantaged students who attended HISD prekindergarten in Stanford scores. Given that the current evaluation highlighted differences in student performance associated with attending HISD prekindergarten, future evaluations should examine additional variables to understand the extent that certain aspects of prekindergarten affect kindergarten performance.