The components involved in adolescent reading are complex and not clearly understood in struggling readers. Phrase reading, a language skill associated with prosodic understanding of syntactic phrases, has received little attention. We studied 70 adolescent readers including delayed readers to answer the following questions: (a) Do phrase-reading ability, syntactic awareness, passage-reading rate, and reading comprehension have a positive, significant correlation; (b) Do language-related variables (i.e., phrasing ability, syntactic awareness) account for more of the variance in comprehension than passage-reading rate; (c) Does phrase-reading ability, as measured by phrase-level prosody, provide a mechanism for, or at least partially mediate, how passage-reading rate and syntactic awareness affect reading comprehension? Data were analyzed using hierarchical regression and mediation regression. All answers were affirmative suggesting that researchers studying adolescent struggling readers should investigate prosodic phrasing-reading ability as a tool for improving reading comprehension.