The evolutionary origin of fruits played a pivotal role in promoting the dominance of angiosperms on the Earth as the fruits protect and nourish seeds and facilitate their dispersal through diverse mechanisms. Understanding the molecular networks underlying fruit development is a prerequisite for elucidating evolutionary mechanisms shaping fruit diversification, and particularly improving crop yield and quality of fruit in response to the rapid climate change in modern agricultural systems. In this article, we offer a comprehensive analysis of fruit classification, emphasising the intrinsic characteristics and their adaptive dispersal strategies in specific environments. Based on the studies in the model systems such as Arabidopsis thaliana and Solanum lycopersicum, we highlight recent advances in identifying novel components of the molecular networks involved in fruit development. We further discuss the evolutionary mechanisms that contribute to fruit diversification in the context of well-established phylogenetic frameworks, with examples from the Brassicaceae and Solanaceae families. A comparison between Brassicaceae and Solanaceae indicates the key module of fruit development is largely conserved in evolution. We propose the future research that integrates multidisciplinary evidence could help to better understand the mechanisms of fruit development and diversification, which ultimately contribute to improving crop yield and quality in practice.