Purpose: Speech reading, or the ability to identify speech components from visual cues of the face, contributes to the development of phonological awareness, which in turn supports reading acquisition. The left superior temporal sulcus (STS) is a key region known to be involved in multisensory integration of speech stimuli. Previous studies have shown a behavioral relation between speech reading and reading skill and, separately, engagement of the STS in audiovisual integration for speech reading and word reading. No prior study has directly demonstrated that speech reading mechanisms in the STS are related to word reading skill. Method: In the current study, we evaluate the role of the left STS in 10- to 16-year-old hearing children (N = 39) during a speech reading task and during phonological processing of visual words to examine the extent to which the left STS is involved with reading skills. Results: Based on a series of preregistered and exploratory analyses, we report three main findings. First, the left STS, functionally localized using an independent speech reading task, was engaged during a visual word-rhyming task. Second, there was weak evidence that the activation of the left STS during word rhyming was related to word reading skills. Third, there was strong evidence that reading skill was more strongly related to phonological processing in the STS than to semantic processing. Conclusion: Our results suggest that better reading skill relies on more robust engagement of specific phonological mechanisms in the STS.