Alarm about the increasing prevalence of childhood obesity has focussed attention on individual lifestyle behaviours that may contribute to unhealthy weight. More distal predictors such as maternal employment may also be implicated since working mothers have less time to supervise children's daily activities. The research reported here used two waves of data from the Longitudinal Study of Australian Children to investigate whether mothers' hours in paid work shape young children's television viewing, snacking and physical activity, and through those lifestyle behaviours, children's weight at ages 4-5 years and 6-7 years. At both ages, children's lifestyle behaviours were interrelated and associated with weight status. Cross-sectional analysis confirmed small, direct associations between longer hours of maternal employment and child weight at age 4-5 years, but not with child's weight measured two years later. In both the cross-sectional and prospective analyses, the children of mothers who worked part-time watched less television and were less likely to be overweight than children of mothers who were not employed or who worked full-time. While associations were small, they remained significant after adjustment for maternal weight, household income and other factors. The combination of direct and indirect relationships between mothers' work hours and the weight status of their young children provides additional support to calls for family-friendly work policies as an important means for promoting healthy family lifestyles and early childhood wellbeing.