This study examined the development of teacher–child conversations in the context of a three-year-long professional development on dialogic reading. Five early education teachers and their story groups, comprising three to six five-year-old Finnish-speaking children from three different cohorts, participated in the study. Thirty reading aloud sessions, 10 from each cohort, were video-recorded in the fall and spring semesters. The dynamics of teacher–child conversations were analyzed using the initiation–response–follow-up framework. We explored the development of teachers’ initiations and follow-ups, and the within-cohort changes in children’s responses. Sequential relationships between teachers’ initiations and follow-ups and the different types of children’s responses, as well as conversational lengths, were examined. The results showed an upward trend in the number of teachers’ initiations and follow-ups during each cohort period. Children’s literal responses were the most prevalent. Positive within-cohort improvement was found in children’s inferential responses, along with a small but meaningful dose of creative type of talk. Sequential analysis showed that teachers’ closed questions strongly determined children’s literal responses, and the probability of children’s inferential responses to teachers’ open-ended questions increased. Lengthier conversations were linked to teachers’ open-ended questions and the use of explorative questions. We discuss the theoretical and practical underpinnings of teacher change in relation to dialogic reading practices.