This book constitutes the refereed proceedings of the 15th Australasian Conference on Data Mining, Aus DM 2017, held in Melbourne, VIC, Australia, in August 2017.The 17 revised full papers presented together with 11 research track papers and 6 application track papers were carefully reviewed and selected from 31 submissions. The papers are organized in topical sections on clustering and classification; big data; time series; outlier detection and applications; social media and applications.