BACKGROUND Malnutrition is a problem globally, cutting across all age groups and its manifestations ranging from undernutrition to overnutrition. However, the scope of this study is confined to malnutrition in under-five children. Childhood malnutrition is amongst the most serious health issues facing sub-Saharan Africa with resulting high rate of morbidity and mortality. The impact of the family on the nutritional status of under-five cannot be overemphasised. This is because the nutritional status of children is closely related to the conditions of their family, which are a determining factor for both food consumption and health care. Although, several studies have been done on the nutritional status of under five children in Nigeria, there is still scanty information on the effect of family socio-economic status in conjunction with family functionality on the nutritional status of under-five children. OBJECTIVE To assess how family socio-economic status and functionality affect the nutritional status of under-five children at General Outpatient Clinic of Baptist Medical Centre, Saki in order to recommend nutritional and family environment screening thereby reducing the burden of malnutrition in Nigeria. METHOD An analytical cross-sectional hospital-based study was conducted from August to November 2018 in the General outpatient clinic of the Baptist Medical Centre, Saki. Data was collected on socioeconomic status from 267 respondents using interviewer administered questionnaire and family APGAR questionnaire was used to collect data on family functionality. The anthropometric measurements included weight, height, mid-upper arm circumference, head and chest circumference. The standard deviation, Z-score for height for age (HAZ), weight for age (WAZ) and weight for height (WHZ) were calculated using reference data from the World Health Organisation in ENA (Emergency Nutrition Assessment) 2011 software for SMART. Children were classified as stunted, underweight or wasted, if their HAZ, WAZ or WHZ was less than -2 standard deviation Z-scores respectively. Children with WHZ more than 2 standard deviation were classified as overweight. The data were collected and analysed using SPSS version 25 statistical package. RESULTS The results were represented with tables and charts. This study found that the prevalence of malnutrition among under five children was as follow: 29.2% of them were stunted, 19.1% were underweight, 13.1% were wasted and 13.9% were overweight. More of the caregivers were traders (44.9%), had tertiary education (55.8%), were from a middle social class (48.7%), middle-income earners (70%) and had poor household wealth index (40.1%). Also, majority (68.9%) of the subjects were from a functional family. Stunting was significantly associated with household wealth and social class of the caregivers (p <0.05); underweight was significantly associated with caregiver social class and household wealth (p<0.05), and wasting was significantly associated with the education of primary caregivers (p<0.05). Stunting, underweight and wasting were all less common in the functional families, but the associations were not statistically significant (p>0.05)