The present study has explored mother–child relationships in the intake of different food groups and the sex differences in these relationships. A population-based sample of 471 mother–child pairs from Stockholm completed a dietary questionnaire to assess habitual dietary intake. Girls showed overall stronger correlations with their mothers' diet than boys did. The strongest correlations found, in both girls and boys, were for the intakes of fruit juice and sweet bakery goods (r 0·30–0·37, P < 0·001). There was a wide range in correlation strength between food groups. Milk/yoghurt and desserts showed no mother–child relationship at all. Breakfast cereals was the only food group with a significant sex interaction (P = 0·01; mothers–girls, r 0·30, P < 0·001; mothers–boys, r0·05, NS). There were significant positive correlations between mothers and daughters in the intake of all macronutrients, whereas none between mothers and sons (sex interactions: protein, P = 0·001; fat, P = 0·004; carbohydrates, P = 0·001). Mothers and daughters (r 0·29, P < 0·001), but not mothers and sons, showed significant correlation in total energy intake, (P = 0·001 for sex interaction). There were generally more differences between mothers and children than between boys and girls in the relative intake (percentage of energy) of different food groups. Since teenaged children have a similar intake of especially snack foods as their mothers, it could be meaningful to educate mothers when aiming at improving the diet of teenaged children, both boys and girls.