Introduction: Malnutrition is the most common nutritional disorder in developing countries and it remains one of the most common causes of morbidity and mortality among children worldwide. Therefore, the current study aimed to assess the prevalence of wasting and its associated factors among under-five children in Marrakesh province in Morocco. Method: A community-based cross-sectional study design was used to determine the prevalence of wasting and its associated factors among under-5 years old children. A structured questionnaire was used to collect data from 430 children paired with their mothers. Anthropometric measurements and determinant factors were collected. SPSS version 19.0 statistical software was used for analysis. Multivariate logistic regression analysis was conducted to identify factors associated to the wasting of the children. Statistical association was declared significant if p value was less than0.05. Results: In this study, the prevalence of wasting was 9.3%. The proportions of severe and moderate wasting children were 6.5% and 2.8%, respectively. Higher odds of wasting children among illiterate mothers were 17 times more likely compared with mothers with high levels (ORa = 17.17; 95% CI: 1.01–13.70). In line with this, the odds of wasting children among lower household incomes were 13 times more likely when compared to those with higher household incomes (ORa = 13.114; 95% CI: 1.13–7.60). Similarly, the odds of wasting children among mothers primiparous were 12 times more likely compared with multiparous (ORa = 12.88; 95% CI: 1.04–4.08). The odds of wasting children were more observed among children who did not benefit from exclusive breastfeeding (ORa = 12.297; 95% CI: 2.47–13.03, 1.03–5.34). Conclusions: The current study showed that the prevalence of wasting among under-five children in Marrakesh province was relatively common. Mother’s education level, household income, parity, and exclusive breastfeeding were significantly associated with wasting. Therefore, nutritional educational intervention programs in Marrakesh province should focus on these factors.