"Sound Partners" (Vadasy et al., 2004) is a phonics-based tutoring program that provides supplemental reading instruction to elementary school students grades K-3 with below average reading skills. The program is designed specifically for use by tutors with minimal training and experience. Instruction emphasizes letter-sound correspondences, phoneme blending, decoding and encoding phonetically regular words, and reading irregular high-frequency words, with oral reading to practice applying phonics skills in text. The program consists of a set of scripted lessons in alphabetic and phonics skills and uses Bob Books[R] beginning reading series as one of the primary texts for oral reading practice. The tutoring can be provided as a pull-out or after-school program, as well as by parents who homeschool their children. The What Works Clearinghouse (WWC) reviewed 18 studies of "Sound Partners" for beginning readers. Four of these studies meet WWC evidence standards; three studies meet WWC evidence standards with reservations; the remaining 11 studies do not meet either WWC evidence standards or eligibility screens. Based on the seven studies, the WWC found positive effects in alphabetics, fluency, and comprehension and no discernible effects in general reading achievement for beginning readers. The conclusions presented in this report may change as new research emerges. Appendices include: (1) Study characteristics; (2) Outcome measures; (3) Summary of study findings included in the ratings; (4) Summary of subscale findings; (5) "Sound Partners" ratings; and (6) Extent of evidence by domain. (Contains 10 footnotes.)