Objective: To determine the impact of weaning type (complementary feeding) and age on the nutritional status of children under five. Material and Methods: This is a case-control study was conducted at the Nutritional Rehabilitation Unit (NRU) of the Pediatric Department of Khyber Teaching Hospital over six months from January 2023 to June 2023, and included children aged 6–59 months, excluding those with congenital abnormalities, mental impairment, and chronic disorders. A questionnaire was provided to parents, gathering data on weaning procedures and anthropometric measures (weight and height for age and Z score). Data were examined using SPSS version 25.0, investigating the odds ratio between weaning practices and nutritional status. Results: The study included 420 children, 140 cases (malnourished children), and 280 controls (healthy children). The participants’ average age was 12.4 months for cases and 13.2 months for controls. The majority of participants (49.76%) were male. Weaning before 6 months was shown to be substantially linked with underweight (OR=1.87, 95% CI=1.12-3.12) and stunting (OR=2.45, 95% CI=1.31-4.58). Conclusion: This study highlights the association between stopping breastfeeding inappropriately and poor nutrition. It also emphasizes the need to promote appropriate weaning practices and improve the nutritional value and diversity of weaning meals to improve child nutrition.