The Okun’s Law reveals the relationship between unemployment rate and economic growth through an empirical study using US quarterly data. This paper investigate the equilibrium relationship between unemployment rate and economic growth in the context of Sri Lankan economy over the period of quarter 1, 2003 to quarter 1, 2015. This empirical analysis has employed the difference model, dynamic model, error correction model and vector error correction model to validate the relationship between unemployment rate and economic growth suggested by Okun’s Law. The error correction and vector error correction models in this empirical study specify that, there is short run and long run equilibrium relationship between unemployment rate and economic growth in the Sri Lankan economy.