This study longitudinally investigated the relation between theory of mind (ToM) and verbal language skills in 231 children from preschool to early adolescence. Further, links to reading comprehension of texts at age 13;7 (years;months) were examined. To assess ToM, children completed false belief tasks at 5;6 and the Strange Stories at 12;8. To assess language, children completed a receptive grammar/sentence comprehension test at 3;6 and 5;6, a receptive vocabulary test at 3;6, 5;6 and 12;8, as well as a test of listening comprehension of texts at 13;7. A bidirectional relation between early and advanced measures of children’s language skills and ToM was found: Changes in ToM were predicted by language skills, especially by receptive grammar/sentence comprehension; changes in children’s receptive vocabulary were predicted by early ToM. However, early ToM had no direct or indirect effect on later listening comprehension or reading comprehension after controlling for early language skills. Only children’s advanced ToM had a small indirect effect on reading comprehension, via listening comprehension. The results are discussed in light of ToM stability over time, and theories on how language and ToM development are intertwined.This study longitudinally investigated the relation between theory of mind (ToM) and verbal language skills in 231 children from preschool to early adolescence. Further, links to reading comprehension of texts at age 13;7 (years;months) were examined. To assess ToM, children completed false belief tasks at 5;6 and the Strange Stories at 12;8. To assess language, children completed a receptive grammar/sentence comprehension test at 3;6 and 5;6, a receptive vocabulary test at 3;6, 5;6 and 12;8, as well as a test of listening comprehension of texts at 13;7. A bidirectional relation between early and advanced measures of children’s language skills and ToM was found: Changes in ToM were predicted by language skills, especially by receptive grammar/sentence comprehension; changes in children’s receptive vocabulary were predicted by early ToM. However, early ToM had no direct or indirect effect on later listening comprehension or reading comprehension after controlling for early language skills. Only children’s advanced ToM had a small indirect effect on reading comprehension, via listening comprehension. The results are discussed in light of ToM stability over time, and theories on how language and ToM development are intertwined.