Many vegetable crop plants, including tomato, have high water needs. The optimal water supply is essential for successful production since most of the tomato cultivars are drought-sensitive, especially at the reproductive stage. One of the options to overcome the negative effects of water reduction on yield is the use of deficit irrigation methods. Detailed knowledge on the effects of different irrigation methods on fruit developmental processes could be a critical factor to analyse the effect on final yield. It is well known that water reduction limits fruit growth rate and final fruit size in tomato, as a consequence of impact on cell division and expansion processes. This paper reviews the roles of cellular traits in the responses of tomato fruit growth to deficit irrigation (DI) were assessed using wild type (WT) and its flacca mutant deficient in ABA. We specifically addressed how cell number, cell size and setup of pericarp cell layers were affected by water deficit during fruit development. Micromorphological analysis of pericarp cell layers showed that DI induced in flacca a stronger negative effect on cell division and expansion than in WT at an early stage of fruit development, but in ripe fruit, the effects of DI were similar in flacca and WT. The main difference between flacca and WT responses to water restriction was a stronger negative impact during early cell division phase in flacca, which is consistent with the involvement of ABA in the cell division process and water-stress-induced ABA synthesis in WT.