Most psycholinguistic models of reading aloud and of speech production do not include linguistic representations more fine-grained than the phoneme, despite the fact that the available empirical evidence suggests that feature-level representations are activated during reading aloud and speech production. In a series of masked-priming experiments that employed the reading aloud task, we investigated effects of phonological features, such as voicing, place of articulation, and constriction location, on response latencies in English and Russian. We propose a hypothesis that predicts greater likelihood of obtaining feature-priming effects when the onsets of the prime and the target share more feature values than when they share fewer. We found that prime-target pairs whose onsets differed only in voicing (e.g., /p/-/b/) primed each other consistently in Russian, as has already been found in English. Response latencies for prime-target pairs whose onsets differed in place of articulation (e.g., /b/-/d/) patterned differently in English and Russian. Prime-target pairs whose onsets differed in constriction location only (e.g., /s/ and /[voiceless retroflex fricative]/) did not yield a priming effect in Russian. We conclude that feature-priming effects are modulated not only by the phonological similarity between the onsets of primes and targets but also by the dynamics of feature activation and by the language-specific relationship between orthography and phonology. Our findings suggest that feature-level representations need to be included in models of reading aloud and of speech production if we are to move forward with theorizing in these research domains.