This thesis explores the physical activity experiences of Aboriginal and Torres Strait Islander mothers from a health promotion viewpoint, in which the determinants of physical activity can be understood. Although regarded as highly inactive subgroup of the population, little is known about the influence the determinants of health have on Aboriginal and Torres Strait Islander mothers’ physical activity participation. Therefore it is difficult to understand how future interventions could be developed to improve physical activity levels and probably explains why so few exist. The central argument of this thesis was that standardised, ‘one size fits all’ approaches, targeted at the majority are ineffective if they did not address the needs of specific groups and populations. Physical inactivity is a serious public health issue for all Australians, in particular the Aboriginal and Torres Strait Islander population, who suffer the greatest burden of disease. Hence, efforts to close the gap are needed by promoting physical activity, which is noted as the second most modifiable risk factor to chronic disease. In order to do this a comprehensive understanding of the factors that influence participation is needed. Whilst limited information that documented the physical activity determinants of Aboriginal and Torres Strait Islander mothers was available, the influences of the broader determinants were examined. The World Health Organization’s social determinants of health were used as framework to understand the various influences that impacted Aboriginal and Torres Strait Islander women’s lives. The purpose of this initial investigation was to contextualise physical activity behaviour. At this point however, it was discovered that the evidence base of the broader Australian maternal population was also relatively small. Therefore, pilot work was conducted to strengthen the knowledge and approach that would be taken in the main study.