The aim of this study was to estimate dietary habits and dietary antioxidant intake in a Polish adult population in relation to socioeconomic status. The subjects (4774) were participants in the Polish National Multi-Centre Health Examination Survey (the WOBASZ II study) performed in 2013–2014. Socioeconomic status (SES) scores were calculated by multiplying ordinal numerical values assigned to consecutive categories of education level and monthly income per capita in a family. In the Polish adult population, a higher socioeconomic status was significantly associated with a better lifestyle (more physical activity and less smoking), a better health status (lower occurrence of overweight individuals and metabolic syndrome in both genders, and lower occurrence of central obesity, hypertension, and diabetes in women), and better dietary habits, including a higher intake of dietary antioxidants.