We examined the importance of children’s classroom activity, defined as task-focused versus task-avoidance behavior, on different literacy outcomes in an orthographically consistent language. Greek children (n =95) were tested in kindergarten, grade 1, and grade 2 on measures of general cognitive ability, phonological awareness, RAN, and short-term memory. The teachers of the children also assessed their task-focused behavior. Nonword decoding, reading fluency, spelling, and reading comprehension measures were administered in grades 2 and 3. The results indicated that task-focused behavior accounted for unique variance in spelling and reading comprehension, even after controlling for the effects of autoregressor, non-verbal IQ, and phonological processing.