This study aimed to identify sustainable development practices for developing cross-cultural management effectiveness in Australian and Singaporean expatriate managers. Australian managers continue to be rated poorly in cross-cultural effectiveness by Asian business executives, and Singaporean expatriates have experienced cross-cultural ineffectiveness business interactions in China and elsewhere. Human resource development programs in cross-cultural management are infrequently utilised by Australian and Singaporean companies, being largely seen by these companies as a low business priority. Research examining the quality of relevant human resource development practices from the perspectives of 51 Australian expatriate managers in Singapore, Singaporean expatriate managers in Australia, and relevant HR professionals is described. Proposals for improved human resource development practices are critically examined, focussing on in-post training, the rise of coaching and mentoring, the development of socio-cultural competencies, and the development of culturally divergent management skills.