Two studies investigated the importance of phoneme awareness relative to other predictors in the development of reading and spelling among children learning a consistent orthography (Czech) and an inconsistent orthography (English). In Study 1, structural equation models revealed that Czech (n=107) and English (n=71) data were fitted well by the same predictors of reading and spelling. Phoneme awareness was a unique predictor in all models. In Study 2, Czech (n=40) and English (n=27) children with dyslexia showed similar deficits on phoneme awareness relative to their age- and spelling-matched control peers. Phoneme awareness appears to be a core component skill of alphabetic literacy, which is equally important for learners of consistent and inconsistent orthographies.