This study examines the impact of terrorism on Karachi stock market returns. Daily data of KSE100 index from 1st July 1999 to 31st December 2015 is used for the empirical analysis. The objective of this paper is to examine the change in systematic risk in response to the terrorist activities. Multiscale data derived from Maximal Overlap Discrete Wavelet Transformation (MODWT) was used to test the heterogeneous market hypothesis. The results showed no relationship between Terrorism and increase in the systematic risk for KSE100 index returns mainly in short-run.