This study investigates the relationship between sea surface temperature (SST) variability occurring over the Indian Ocean and winter rainfall variability in eastern Australia. Six indices of SST variability are compared and their relationship to rainfall over eastern Australia is determined. An analysis of historical rainfall data for Queensland, New South Wales, and Victoria reveals that a strong relationship exists between a number of these indices and winter rainfall. In particular, anomalous SSTs over the Indonesian region provide a good indication of winter rainfall variability in eastern Australia. Additionally, this relationship is shown to hold true irrespective of potential impacts on rainfall by the El Ni¿o--Southern Oscillation (ENSO). A possible physical process by which the Indian Ocean SST anomalies may influence winter rainfall is proposed, involving their impact on the nature of the northwest Australian cloud band. This study demonstrates marked controls on winter climate variability comparable to that induced in summer by the better known ENSO processes and hence offers improved understanding of year-round seasonal climates.