There is a pressing need for a homogonous tsunami catalogue for the Indian Ocean as nearly 20 per cent of tsunami events worldwide affect the region. Any study on tsunami hazard assessment necessitates a homogenous tsunamigenic earthquake catalogue. The existing records of strong tsunamigenic earthquakes have the magnitudes expressed in Moment magnitude (MW), Body wave magnitude (mb), Local magnitude (ML) and Surface wave magnitude (MS). This study deals with developing regional magnitude correlation equations for tsunamigenic earthquakes of the Indian Ocean. The present investigation estimates the threshold magnitude and focal depth for an earthquake to turn tsunamigenic. It is found that earthquakes above MW ≥ 5.2 and focal depth ≤ 80 km have the potential to generate a tsunami in the region. Since the moment magnitude is the most scientific and reliable scale that describes earthquakes' physical size, equations have been developed to convert surface wave magnitude (MS) to moment magnitude (MW). Three types of regression models have been used, viz. Orthogonal Standard Regression (OSR), Standard Regression (SR) and Inverse Standard Regression (ISR). The efficacy of these models has been compared in terms of R-Squared and residual analysis. This study indicates that OSR (Orthogonal Standard Regression) is the best-suited regression model for developing magnitude correlation equations for the region. Magnitude conversion equations for three zones of the Indian Ocean have been created. Additionally, a single unified conversion equation for the whole of the Indian Ocean has also been derived with rational accuracy.