This study assesses changes in the technical efficiency of commercial banks in Sri Lanka following the end of armed conflict in 2009. The weighted aggregate-efficiency technique, based on a group-wise heterogeneous subsampling bootstrap approach, is employed to compare efficiency levels during the periods 2007-2009 and 2010-2013. This technique allows for heterogeneity in environmental and regulatory conditions between the two periods while assuming homogeneity within each period. Our results reveal that the banking sector experienced a significant efficiency improvement post-conflict even with unprecedented branch expansion. The findings, therefore, controvert the mainstream view that bank efficiency declined with rapid industry expansion. Further, we conclude that geographical expansion of the banking sector is a viable and effective policy tool to achieve broad-based and inclusive growth for emerging economies like Sri Lanka, particularly in a period of post-conflict recovery.