Evidence accumulated to date suggests that excess weight in the adult population is associated with a wide range of impairments in executive function. However, most studies have only examined the influence of body mass index (BMI) on the cognitive function of individuals with overweight and obesity. This study examined the potential associations of markers of adiposity (BMI, body fat, and visceral fat) with five domains of executive function including cognitive flexibility, inhibition, monitoring, planning, and working memory in a sample of 87 adult with overweight (n = 34) and obesity (n = 53). The results show that obese people had poorer working memory than those with overweight. After controlling for educational levels and physical activity, the results suggest that neither the waist–hip index not visceral fat were associated with cognitive function. In overweight, body fat was negatively associated with executive components of inhibition (p = 0.05) and monitoring (p = 0.02). In the obesity subgroup, body fat was negatively associated with inhibition (0.02) and working memory (0.04). The results provide evidence of the importance of adiposity for cognitive function. The implications for understanding the influence of markers of adiposity in adults with overweight and obesity are discussed.