<p>The Indian Ocean Dipole (IOD) is a significant driver of ocean-atmosphere coupled phenomena over the equatorial Indian Ocean (IO), and it strongly influences the inter-annual rainfall variability of Sri Lanka. Notably, the relationship between IOD and Sri Lanka rainfall has undergone notable fluctuations over the past decades. This study analyzes the relationship between the IOD and rainfall in the wet zone of Sri Lanka during the peak IOD season (September-October-November) utilizing reanalysis datasets and historical simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6). It has been demonstrated that there is a weak and insignificant correlation (<i>r</i> = 0.07) between the IOD and rainfall over the wet zone of Sri Lanka during the pre-1980s. On the other hand, a strong and significant correlation (<i>r</i> = 0.72) was observed during the post-1980s. Furthermore, we found that positive IOD warming was higher in the post-1980s compared to the pre-1980s. This was attributed to stronger walker circulation, which in turn resulted in stronger moisture convergence and convection over the western IO. As a result, an enhanced relationship between rainfall over the wet zone of Sri Lanka and IOD. Thus, this study highlights how changes in the ocean-atmosphere interactions in the tropical IO have strengthened the relationship between the IOD and Sri Lanka’s rainfall in recent decades. These findings could be valuable for seasonal prediction in Sri Lanka.</p>