Currently, organic photocatalyst-based photocatalysis has garnered significant attention as an environmentally friendly and sustainable reaction system due to the preferable structural flexibility and adjustable optoelectronic features of organic photocatalysts. In addition, π-π interactions, as one of the common non-bonded interactions, play an important role in the structure and property adjustments of organic photocatalysts due to their unique advantages in modulating the electronic structure, facilitating charge migration, and influencing interfacial reactions. However, studies summarizing the relationship between the π-π interactions of organic photocatalysts and their photocatalytic performance are still rare. Therefore, in this review, we introduced the types of π-π interactions, characterization techniques, and different types of organic photocatalytic materials. Then, the influence of π-π interactions on photocatalysis and the modification strategies of π-π interactions were summarized. Finally, we discussed their influence on photocatalytic performance in different photocatalytic systems and analyzed the challenges and prospects associated with harnessing π-π interactions in photocatalysis. The review provides a clear map for understanding π-π interaction formation mechanism and its application in organic photocatalysts, offering useful guidance for researchers in this field.