Complementary feeding practices during the critical window of 6-23 months strongly influence child growth, yet the interplay between feeding practices, food insecurity and early food preferences remains poorly understood in marginalised urban communities (1). This study aimed to assess complementary feeding practices, household food insecurity and food preferences, and explore their associations with growth outcomes among young children in Shireen Jinnah Colony, a low-income settlement in Karachi, Pakistan. An explanatory sequential mixed-methods design was employed. In the quantitative phase, a cross-sectional household survey was conducted with n = 214 mother-child dyads (children aged 6-23 months) selected through systematic random sampling. Complementary feeding practices were assessed using World Health Organization infant and young child feeding indicators, including timely introduction, minimum dietary diversity, minimum meal frequency and minimum acceptable diet. Household food insecurity was evaluated using the Household Food Insecurity Access Scale (2). Caregiver-reported acceptance of foods representing five basic taste categories (sweet, salty, sour, bitter and umami) was assessed. Child anthropometry was assessed using World Health Organization z-scores for height-for-age, weight-for-age and weight-for-height. Multivariable logistic regression examined associations between complementary feeding practices, food insecurity, food preferences and growth outcomes, adjusting for child age, maternal education and household income. In the qualitative phase, four focus group discussions (n = 32 mothers) purposively selected from households with varying complementary feeding adequacy explored feeding practices and barriers, analysed using inductive thematic analysis. Only 28.5% of children received a minimum acceptable diet, and 41.3% met minimum meal frequency. The prevalence of stunting, underweight and wasting was 43.7%, 30.1% and 16.4%, respectively. Severe household food insecurity was reported by 41.1% of households. Children not receiving a minimum acceptable diet had significantly higher odds of stunting (adjusted odds ratio 2.68, 95% confidence interval 1.54-4.66, p < 0.001) and stronger sweet taste preference (adjusted odds ratio 2.15, 95% confidence interval 1.23-3.76, p = 0.007) than those receiving adequate complementary feeding. Household food insecurity was independently associated with inadequate meal frequency (adjusted odds ratio 2.31, 95% confidence interval 1.29-4.13, p = 0.005). Qualitative analysis revealed four themes: delayed introduction of complementary foods due to cultural beliefs, reliance on low-cost energy-dense foods, limited exposure to diverse tastes, and maternal employment reducing feeding frequency. Triangulated findings indicated that inadequate complementary feeding, food insecurity and limited taste exposure were synergistically associated with narrow food preferences and growth faltering. These findings highlight the need for interventions promoting timely and adequate complementary feeding alongside household food security and early taste exposure in urban settlements of Karachi.