The Optional Flexible School Day Program (OFSDP) is approved by the Texas Commissioner of Education and is offered by the Houston Independent School District (HISD) to provide students with flexible school hours and days of attendance. The goal of the program is to improve the graduation rates for students who are in danger of dropping out of school or who have dropped out, or for students who are behind in core subject courses. The program provides students with opportunities to earn attendance and course credits if they are unable to attend school in a traditional setting or are at risk of being denied course credit due to unmet attendance requirements. This report describes characteristics of program participants and their academic outcomes for 2015-2016. Key findings are as follows: (1) In 2015-2016, 468 HISD students participated in OFSDP, the lowest enrollment since the first full year of program implementation in 2011-2012. This was a 23.2 percent decrease from 609 participants in 2011-2012, as well as a 14.9 percent decrease from 550 participants in 2014-2015; (2) OFSDP participants enrolled in 1,453 courses, completed 79.1 percent of the courses, and earned 479.0 credits; and (3) In 2015-2016, 63 (25.0 percent) of the 252 OFSDP seniors graduated and 33 (13.1 percent) withdrew from HISD schools. By fall of the 2016-2017 school year, 74 (29.4 percent) remained enrolled in the district and 82 (32.5 percent) of OFSDP's 2015-2016 seniors had not yet shown up to continue their education in HISD.