This study investigated the effectiveness of "Solve It!" instruction on students' knowledge of math problem-solving strategies. "Solve It!" is a cognitive strategy intervention designed to improve the math problem solving of middle school students with learning disabilities (LD). Participants included seventh- and eighth-grade students with LD (n = 77) and average-achieving students (n = 77). We examined treatment effects of the intervention, as well as differential effects of treatment across ability levels, on students' knowledge of problem-solving strategies using the Math Problem-Solving Assessment. Results showed that students across ability levels who received "Solve It!" instruction reported using significantly more strategies than students in the comparison group. Implications for instruction are discussed as well as directions for future research. (Contains 2 figures and 2 tables.)