The study examines the determinants of the efficiency effect of Free Trade Agreements (FTAs) on services sector productivity growth in Nigeria from 1970 to 2022. The data was analyzed using the Autoregressive Distributed Lag (ARDL) technique. Empirical results showed that the significant factors responsible for efficiency effect of FTAs on services sector productivity growth in the long run were inflation and corruption. Export competitiveness and democratic accountability were found to be significant factors responsible for the efficiency effect of FTAs on services sector productivity growth in the long run. In the short run, the findings showed that electricity was a significant factor responsible for the efficiency effect of FTAs on services sector productivity growth. It was found that corruption was also a significant factor responsible for the short-run efficiency effect of FTAs on services sector productivity growth. While utilising inflation control, export competitiveness, and democratic accountability, policymakers should concentrate on tackling structural problems like corruption and electricity shortages.