Introduction: Optimal complementary feeding practices after six months are crucial for child growth and development. The COVID-19 pandemic may have disrupted factors influencing these practices, including food security and social support. This study aimed to investigate factors affecting the minimum acceptable diet (MAD) among Indonesian infants aged 6–11 months during the pandemic. Methods: A cross-sectional online survey was conducted as part of the multinational COVID-19 Mom-Infant Study. Convenience sampling recruited 403 mothers living in Indonesia (aged ≥18 years) with infants aged 6-11 months. The Household Food Insecurity Access Scale (HFIAS), UK COVID-19 New Mums questionnaire, and Demographic and Health Survey were used to assess food security, psychosocial and social support, and MAD. Multivariable logistic regression identified MAD determinants. Results: Most mothers were 25-34 years old, had a high level of education, were from middle- to high-income households, were not working, and resided on Java Island. The prevalence of MAD was 74.2%, while 26.6% of households experienced food insecurity. Primary support came from husbands. Bivariate analyses indicated that child’s age, maternal education and employment, maternal mood, household income and food security, husband’s support, and support group were associated with MAD. However, only household food security remained significantly associated with MAD in multivariate analysis (aOR=2.155; 95% CI =1.239–3.750; p=0.007). Conclusion: Household food security was crucial for sustaining infant feeding during the pandemic, particularly in high socioeconomic and urban settings. Targeted interventions should focus on strengthening both the food environment and caregiver’s capacity through adaptive food access strategies and communitybased support.