The 26,000-year long time-series analyzed in a marine sediment core from the northern Bay of Bengal includes Mg/Ca-based SST estimates, Ba/Ca-based mixed layer salinity estimates, and estimates of ice-volume corrected d18O of the mixed layer. The data are provide new insights into the control of Indian Summer Monsoon over the last 26,000 years, including a strong influence of zonal and meridional SST gradient changes within the tropical Indian Ocean on Indian Summer Monsoon variability.