Abstract: Alternative splicing (AS) is a crucial post-transcriptional mechanism in plants, significantly contributing to the diversification of biological processes and adaptive responses. Distinct splice isoforms are generated by exon skipping (ES), intron retention (IR) and other mechanisms, enabling plants to adapt to a range of biotic stresses, including those posed by bacteria, fungi and viruses. Advances in bioinformatics have greatly improved the detection and characterization of AS events, revealing their critical roles in plant immunity. This review highlights the involvement of AS in regulating RNA interference (RNAi), hormone signaling pathways, and immune responses such as pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). In addition, pathogens exploit AS to produce effectors that subvert plant immunity. Beyond its role in natural immunity, AS also holds promise for pesticide development, offering opportunities to enhance plant disease resistance by targeting pest-associated or immunity-related genes. Future research on AS under biotic stress is expected to uncover novel regulatory mechanisms and provide new strategies for crop improvement and sustainable agriculture.