The diffusion mechanism of terrorist shocks to third countries’ stock market responses is explored by employing a Heckit model. Stock market response is broken down to (i) the direction of reaction and (ii) conditional on negative reaction, its magnitude. The analysis puts forward two behavioral factors (memory-based utility/availability heuristic, social amplification of risk), proxied by past terrorism record and terrorism risk concern as the shocks’ diffusion channels. The findings are that the likelihood and the size of negative stock market reaction increase with terrorism record and risk concern. Additionally, weak evidence is uncovered for a mitigation of risk concern's impact by favorable macroeconomic stance. Furthermore, the impact of behavioral factors, especially over the magnitude of reaction, is robust when controlling for economic linkages. The latter are also significant predictors of the direction of stock market reaction, but not of its magnitude.