In developed countries, persons of low socioeconomic status (SES) are generally less likely to consume diets consistent with dietary guidelines. Little is known about the mechanisms that underlie SES differences in eating behaviours. Since women are often responsible for dietary choices within households, this qualitative study investigated factors that may contribute to socioeconomic inequalities in dietary behaviour among women. Semi-structured interviews were conducted with 19 high-, 19 mid- and 18 low- SES women, recruited from Melbourne, Australia, using an area-level indicator of SES. An ecological framework, in which individual, social and environmental level influences on diet were considered, was used to guide the development of interview questions and interpretation of the data. Thematic analysis was undertaken to identify the main themes emerging from the data. Several key influences varied by SES. These included food-related values such as health consciousness, and a lack of time due to family commitments (more salient among higher SES women), as well as perceived high cost of healthy eating and lack of time due to work commitments (more important for low SES women). Reported availability of and access to good quality healthy foods did not differ strikingly across SES groups. Public health strategies aimed at reducing SES inequalities in diet might focus on promoting healthy diets that are low cost, as well as promoting time-efficient food preparation strategies for all women.