Although social capital approach has showed its merits in predicting well-being and health in the working environment, studies examining the relation between social capital and burnout are scarce and limited to cross-sectional studies in the health care sector. This study aims to explore the longitudinal relationship between workplace social capital and burnout in a Belgian company in the energy sector. An additional aim was to assess whether the relation between workplace social capital and the dimensions of burnout was independent of job characteristics, i.e., the level of decision-making autonomy and task variety, and demographical variables. Analyses are conducted on the questionnaire data of 473 workers who participated at the two waves (2013 and 2014) of a longitudinal study. The results showed a negative relation between social capital and distance and a positive relation between social capital and competence, after 1-year follow-up and after adjustments for baseline levels of the respective burnout dimension. In contrast with the literature, no relation between social capital and emotional exhaustion was found after adjustment for baseline level of emotional exhaustion. After additional adjustments were made for the job characteristics 'decision-making autonomy' and 'task variety', the relation between social capital and competence disappeared. This study delivered evidence for the lagged relation between social capital and distance, even after controlling for demographical and job characteristics. Therefore, the findings suggest that organizations should pay attention to strategies enhancing social interaction, enabling to increase the levels of support, reciprocity, sharing and trust, in the prevention of burnout.