Background Adequate breastfeeding and complementary feeding practices are paramount in fragile situations where access to food and healthcare is limited. The objectives of this study are to examine breastfeeding and complementary feeding practices among Syrian refugees and their Lebanese host communities and to investigate the correlates of exclusive breastfeeding (EBF) at four and 6 months in these communities. Methods Using two-stage stratified sampling, a cross-sectional survey was conducted in Akkar, a region with a high density of Syrian refugees in Lebanon, between April and November 2019. In one-to-one interviews, mothers of children (6–24 months) completed a questionnaire including specific questions about breastfeeding and complementary feeding practices, a 24-h recall, and socio-demographic characteristics for 189 Syrian refugees and 182 Lebanese host community households. Descriptive statistics, simple and multiple logistic regression were used in data analysis. Results Among breastfeeding practices, ever-breastfeeding was most prevalent (90%), followed by early initiation of breastfeeding (64.8%), EBF at four (49.6%), and six (36%) months. One in four children was introduced to solids before 6 months of age, and less than a third was given iron-fortified baby cereals as the first complementary foods. Only 24.4% and 9.2% of children met the minimum dietary diversity and minimum acceptable diet requirements, respectively. Compared to children of the Lebanese host communities, those of Syrian refugees had higher rates of EBF at four and 6 months as well as continued breastfeeding at 1 year, whereas only 17.9% of Syrian refugees’ children met minimum dietary diversity compared to 30.9% of Lebanese host community children (p <  0.05). Among refugees, education and spouse’s employment status were associated with higher odds of EBF at 4 months. As for Lebanese households, female children were less likely to be exclusively breastfed at 4 months and 6 months, while a natural delivery increased the odds of EBF at 6 months. Conclusion Breastfeeding and complementary feeding practices are suboptimal among children of Syrian refugees and their Lebanese host communities in North Lebanon. There is a need for intervention strategies to tackle gaps in services and assistance delivery programs to enhance infant and young child feeding practices among both communities.