Croatian language teaching is the most comprehensive subject in the younger grades of primary school, with 175 hours per year and 5 hours per week (Curriculum for the subject Croatian language for primary schools and grammar schools in the Republic of Croatia, 2019). Although children start school at about 7 years old, they start learning the language much earlier, even from the day they are born. They first practice the auditory competence that is innate in them, and then they also acquire the speech competence. However, reading and writing require teaching, and systematic teaching starts from the first grade of primary school and maybe a little earlier, in kindergarten. (Pavličević-Franić, 2005). However, language learning is influenced by many aspects, and some of them are the social environment in which the child grows up, language exposure, kindergarten teachers, teachers, the media and the wider community (Aladrović Slovaček, 2019). In primary school, they start learning a language by initial reading and writing, and then they upgrade their knowledge by teaching communication and language, literature and creativity, and culture and media which mutually interwind. In this study, the aim was to examine whether there is a connection between reading comprehension and spelling knowledge in fourth grade students. The research showed that girls wrote a spelling test better and a comprehension test with a literary-artistic text, and a test with a scientific text was solved equally well by girls and boys. Furthermore, students from Zagreb did better in the spelling test, and students from Šibenik were better in both tests of reading comprehension. Finally, research has shown that there is a connection between spelling knowledge and reading comprehension. Students who solved the part of the test better with comprehension of the reading, also solved the spelling test better. It would be great if this topic did not stop at this research, but if a larger research was done, with a much larger sample of children, and if the test would explore the accompanying influences on spelling knowledge and reading competence such as students' reading habits. subject and attitude towards reading.