Studies on diminutives have primarily focused on European languages and a few African languages. However, the forms and functions of diminutives in the Igbo language remain critically unexplored. This article examines the forms and functions of diminutives in Igbo, as well as accounts for the role of tone in the formation of diminutives in Igbo, using corpus-assisted data. The descriptive analysis reveals that the form of Igbo diminutives can be categorised into synthetic, analytic, and category incorporated. The results show that the suffix -tu is the most productive diminutive marker in Igbo and is used when referring to the contact between entities, temporal shortness (short duration), spatial smallness, small featural differentiation, and politeness. I argue that tone generally does not govern Igbo diminutive constructions. The study contributes to the literature by identifying a third type of diminutives 'category incorporated', which refers to verbal constructions that do not prototypically have explicit diminutive forms or markers but have diminutive meanings. This research provides a distinct perspective on the important role of verbs in the formation of diminutives in the Igbo language.