Many middle-school students struggle with basic reading skills. One reason for this might be a lack of automaticity in word-level lexical processes. To investigate this, we used a novel backward masking paradigm, in which a written word is either covered with a mask or not. Participants (N = 444 [after exclusions]; n[subscript female] = 264, n[subscript male] = 180) were average to struggling middle-school students from an urban area in Eastern Iowa that were all native speakers of English and were roughly equally from grades 6, 7, and 8 (average age: 13 years). Two-hundred-fifty-five students qualified for free or reduced-price lunch, a proxy for economic disadvantage. Participants completed different masked and unmasked task versions where they read a word and selected a response (e.g., a pictured referent). This was related to standardized measures of decoding, fluency, and reading comprehension. Decoding was uniquely predicted by knowledge (unmasked performance), whereas fluency was uniquely predicted by automaticity (masked performance). Automaticity was stable across two testing points. Thus, automaticity should be considered an individually reliable marker/reading trait that uniquely predicts some skills in average to struggling middle-school students.