Given mounting evidence for working memory impairments in dyslexia, letter reversals during rapid automatic letter naming (phonological loop) or rapid automatic letter writing (orthographic loop) may reflect momentary inefficiency of working memory. Few of the children, with or without dyslexia, in a multi-generational family genetics study, produced reversals, but those with dyslexia produced more than those without dyslexia. Working-memory component predictors (word storing and processing units, phonological and orthographic loops, and executive functions) in regressions differentiated children with dyslexia (average age 11) who did and did not make reversals, predicted the number of reversals on specific letter naming or letter writing tasks, and explained unique variance in reading and writing outcomes. Although reversals are not a hallmark defining feature of dyslexia, children who produce reversals may benefit from instruction designed to develop specific working memory components and their efficient coordination in time.