Good and poor comprehenders exhibit different profiles of cognitive abilities, despite comparable decoding skills. Recent work suggests that executive functions, particularly cognitive flexibility, may underlie poor comprehenders' difficulties in childhood and adulthood. However, metalinguistic skills that enable readers to reflect on various aspects of print may also contribute to poor comprehenders' difficulties. We examined metalinguistic abilities (graphophonemic and syntactic) and cognitive flexibility (graphophonological-semantic and syntactic-semantic) in 24 good and 24 poor adult comprehenders, matched on age-appropriate non-word decoding skill and general cognitive ability. Groups differed significantly on graphophonemic awareness, syntactic awareness, and both measures of cognitive flexibility after verbal ability and word identification were controlled. Differences in cognitive flexibility remained significant even when relevant metacognitive skills were controlled. These data demonstrate additional cognitive differences between good and poor comprehenders that can inform theory and practice.