Background: Eating habits and physical activity are important factors for the development and prevention of non-communicable diseases. Therefore, the objective of this study was to analyse the beliefs, behaviours, and experiences of dietary and physical activity habits based on the constructs of the Social Cognitive Theory (SCT). Methods: An exploratory study with a qualitative methodology and a phenomenological study design was conducted using focus groups, in-depth interviews, and indirect non-participatory observation. The sessions were audio-recorded and transcribed with prior written informed consent. Data analysis was performed using a hybrid approach.Results: Workers reported that they do not eat vegetables or fruits daily; however, the consumption of fast food and sugary drinks was frequent. Participants’ behaviour is influenced by environmental factors such as reinforcements (economic bonus and company meetups & events), barriers (workplace policies) and facilitators (availability of drinking water, free tortillas , dining rooms, and recreational areas); and personal factors, such as low self-control when when choosing foods from the grains group (e.g. Mexican pastries, noodles and breads), and emotional confrontation (e.g. few workers try to use strategies to confront their emotions and avoid them from affecting their eating and physical activity). On the other hand, participants indicated not feeling capable of eating specific foods due to their taste, for example vegetables, and doing physical activity due to factors such as time. Finally, other key elements influencing workers’ behaviours were observational learning (participants eating behaviour and physical activity are influenced by their coworkers and family’s behaviours), social support (coworkers and family) and outcome expectations (participants’ hoping to improve their health by eating healthy and physical activity behaviours).Conclusions: Workers’s eating behaviour and physical activity could be modified if different influencing factors are simultaneously addressed. These findings will contribute to the development of worksite health programs, based on the SCT, to address the key factors that could improve workers’ eating behaviours and physical activity. Keywords: Eating habits, physical activity, adults, workers, workplace programs, qualitative research, Social Cognitive Theory.