The study investigates direct and indirect preschool quality effects on emergent literacy skills (children's letter knowledge, oral skills, and interests and skills in print and communication) using quality indicators at process (ECERS-R, ECERS-E), structure (e.g. class size) and belief (e.g. support creativity) level. The study included a sample of 547 children from 97 preschools and implemented standardised tests and teacher-ratings in the final preschool year, as well as observations and questionnaires throughout the preschool period. Multiple regression models reveal that ECERS-R was significantly related to children's teacher rated interest and skills in communication, and that ECERS-E predicted children's tested letter knowledge. Group size predicted children's interest and skills in print negatively, revealing lower scores in larger groups. With regard to beliefs, teachers' creativity and social support beliefs were negatively related with children's letter knowledge, whereas teachers' knowledge- and cultural-tools-oriented beliefs were positively related with interest and skills in communication. These effects were partly mediated through ECERS-E. Although the study provides evidence for effects of preschool quality on the development of children's emergent literacy skills and some evidence that effects of beliefs are partly mediated through process quality, effects are not consistent through the outcome variables and effect sizes are small.