"READ 180®" is a reading program designed for struggling readers who are reading 2 or more years below grade level. It combines online and direct instruction, student assessment, and teacher professional development. "READ 180®" is delivered in 90-minute sessions that include whole-group instruction, three small-group rotations, and whole-class wrap-up. Small-group rotations include individualized instruction using an adaptive computer application, small-group instruction, and independent reading. "READ 180®" is designed for students in elementary through high school. "READ 180®" was found to have positive effects on comprehension and general literacy achievement, potentially positive effects on reading fluency, and no discernible effects on alphabetics for adolescent readers. The What Works Clearinghouse (WWC) identified nine studies of "READ 180®" that both fall within the scope of the Adolescent Literacy topic area and meet WWC group design standards. Three studies meet WWC group design standards without reservations, and six studies meet WWC group design standards with reservations. Together, these studies included 8,755 adolescent readers in more than 66 schools in 15 school districts and 10 states. The WWC considers the extent of evidence for "READ 180®" on the reading achievement of adolescent readers to be medium to large for four outcomes--comprehension, general literacy achievement, reading fluency, and alphabetics. The following are appended: (1) Research details for Fitzgerald and Hartry (2008); (2) Research details for Kim et al. (2010); (3) Research details for Swanlund et al. (2012); (4) Research details for Interactive, Inc. (2002); (5) Research details for Meisch et al. (2011); (6) Research details for Sprague et al. (2012); (7) Research details for White et al. (2006); (8) Research details for White et al. (2005); (9) Research details for Yuchak (2013); (10) Outcome measures for each domain; (11) Findings included in the rating for the comprehension domain; (12) Findings included in the rating for the general literacy achievement domain; (13) Findings included in the rating for the reading fluency domain; (14) Findings included in the rating for the alphabetics domain; (15) Description of supplemental findings for the comprehension domain; (16) Description of supplemental findings for the general literacy achievement domain; (17) Description of supplemental findings for the reading fluency domain; and (18) Description of supplemental findings for the alphabetics domain. An explanation of the WWC Rating Criteria, along with a Glossary, are also included.