Previous studies show that many students with reading and spelling problems have a lack of progress in reading and spelling skills after years of special education services. The aim of the study is to evaluate the reading and spelling skills of Finnish children in grades 1 and 2 receiving part-time special education from special education teachers for reading and spelling difficulties (RSD) and for RSD with other learning difficulties. In this study, the focus is in the roles of the form and the amount of part-time special education in reading and spelling skills development. Of 152 children involved in the study, 98 received part-time special education for RSD, and 54 did not have RSD and did not receive special education. The results showed that the reading and spelling skills of students with RSD lagged behind age level and that students with overlapping difficulties exhibited even slower development. Small group education and a moderate amount of part-time special education (approximately 38 h per year) predicted faster skill development, whereas individual and a large amount of special education (more than 48 h per year) were related to slower skill development and broader difficulties.