This document analyzes the determinants of interest rate spread in the Pakistani banking sector from 2003-2010. It specifies models to examine how bank-specific factors like non-performing loans, liquidity risk, and operational costs, as well as macroeconomic factors like inflation, exchange rates, and money supply, influence interest rate spread. The study finds that most bank-specific and macroeconomic variables have a statistically significant impact on interest rate spread. It concludes that interest rate spread in Pakistan is sensitive to both bank internal conditions and the external macroeconomic environment.