The interaction between lexical and phonological development has been the focus of a growing body of research. Findings suggest that phonological ability influences word learning and that certain characteristics of words influence how words are produced by children. This article summarizes research findings regarding the effects of word frequency, phonological neighborhood density (PND), and phonotactic probability (PP) on phonological development, and describes how these factors have been manipulated to influence phonological learning in the treatment of speech sound disorder in children. Clinical applications and ideas for considering lexical factors in the selection of target words for treatment are provided.