The author investigated whether high levels of metacognitive knowledge about problem solving could compensate for low overall aptitude. To test this hypothesis, a 2 (high–low aptitude) × 2 (high–low metacognitive ability) design was used to analyze children's problem-solving performance. Processing differences between ability groups were determined through an analysis of "think aloud" protocols. Protocols were analyzed at two levels: (a) grouping of subroutines that function as heuristic processes and (b) grouping of subroutines that function as strategies. Regardless of aptitude, higher metacognitive children performed better than the lower metacognitive children. Higher metacognitive ability groups were more likely to rely on hypothetico-deductive (if–then propositions) and evaluation (check the adequacy of a hypothesis) strategies than was the lower metacognitive group. The results are discussed in terms of the independence of metacognition and general academic aptitude. (PsycINFO Database Record (c) 2016 APA, all rights reserved)