This study aimed to examine the amount of lifestyle counseling that Dutch general practitioners (GPs) generally provide to their patients, as well as the behavioral determinants of their lifestyle counseling practices. Lifestyle counseling was defined and operationalized through the 5As model (i.e. Assess, Advise, Agree, Assist and Arrange), while determinants were based on an adapted version of the theory of planned behavior. A cross-sectional study was conducted among a sample of 198 GPs, using an online survey questionnaire for collecting data. The results showed that 79.3% of the GPs assessed patients' current lifestyle often or always, while 60.1% reported they often or always assessed patients' motivation to improve their lifestyle. Depending on the lifestyle behavior, Advising to improve lifestyle ranged from 42.5% (sleep) to 92.4% (smoking), while Agree to set goals ranged from 21.7% (sleep) to 46.9% (smoking). Assisting patients to overcome barriers to lifestyle changes varied per patient barrier, ranging from lack of financial resources (25.7%) to stress (81.8%). The findings from the linear hierarchical regression revealed that GPs' self-efficacy (β = .46, p < .001), patient norm (β = .21, p < .001), and attitude (β = .20, p < .05) were the determinants with the strongest associations with lifestyle counseling. The full model explained 47% of the variance in counseling lifestyle. Implications for supporting GPs to counsel patients about their lifestyle are discussed.