Although northwestern Indian Ocean has experienced some deadly tsunamis in the past, this region remains one of the least studied regions in the world and little research work has been devoted to its tsunami hazard assessment. In this study, we compile and analyze historical tsunami in the northwestern Indian Ocean and present a tsunami list for this region. Then, a deterministic method has been employed to give a preliminary estimation of the tsunami hazard faced by different coastlines in this region. Different source scenarios are considered and for each scenario, numerical modeling of tsunami is performed. For each case, the maximum positive tsunami wave heights along the coasts are calculated which provide a preliminary estimation of tsunami hazard and show which locations face the greatest threat from a large tsunami.