Abydos is a professional development program that includes a three-week writing institute. It provides school districts with teachers who, after a year of implementation and another year of professional development, can train other teachers, thus providing ongoing staff development. The Houston Independent School District (HISD) implemented Abydos during 2013-2014 academic year. The purpose of this report was to examine the impact of Abydos on fourth and seventh grade students' writing performance on the 2014 STAAR writing subtest based on the level II, phase-in 1 standard. The following research questions were addressed: (1) How did students whose teachers completed Abydos training perform on the 2014 STAAR writing subtest compared to their grade-level peers whose teachers did not attend Abydos training?; and (2) Did the impact of Abydos on students' writing performance vary by student group? Student writing performance data were collected from two test assessments: STAAR writing test and Stanford Achievement Test (Stanford 10) reading and language subtests. Recommendations include: (1) Based on students' outcome data, there is no strong evidence showing Abydos training had a significant positive impact on students' performance. The Curriculum, Instruction, and Assessment Department may collect the data regarding teacher implementation of Abydos writing strategies in the classroom to explore the influence of Abydos training on teacher's instructional practices; and (2) Future evaluations should also include teacher interviews to find out whether Abydos training fosters changes in teachers' attitudes and their implementation of instructional model for improving writing strategies in the classroom.