The COVID-19 pandemic presents a global crisis and authorities have encouraged the population to promote preventive health behaviors to slow the spread of the virus. While the literature on psychological factors influencing health behaviors during the COVID-19 is flourishing, there is a lack of cross-national research focusing on multiple health behaviors. The present study overcomes this limitation and affords a validation of the Theory of Planned Behavior (TPB) as a conceptual framework for explaining the adoption of handwashing and limitation of social contacts, two health behaviors that highly differ in their nature. Specifically, we compare TPB model on these two protective behaviors among people living in Belgium (N = 3744) and France (N = 1060) during the COVID-19 sanitary crisis. Data were collected from March 18 until April 19, 2020, which corresponds to the spring lockdown and the first peak of the pandemic in these countries. Results indicated that more positive attitudes, greater social norms, increased perceived control and higher intentions were related to higher adherence to handwashing and limitation of social contacts, for both Belgian and French residents. Ultimately, we argued that the TPB model tends to manifest similarly across countries in explaining health behaviors, when comparing handwashing and limitation of social contacts among individuals living in different national contexts.