Despite being the European Union country with the second largest wooded area and the fourth in terms of forest occupation with respect to its territory, only 9.47% of the forest area in Spain is certified by one of the two most important forest certification systems (PEFC and FSC). The literature review has shown that forest certification drivers may be divided into five main mechanisms. The first three are external: Market, Signalling and Legal mechanisms, and the last two internal: Moral and Learning mechanisms. 124 completed questionnaires out of 1194 certified companies in Spain were received to carry out a descriptive and a cluster analysis of the main motivations that encourage the adoption and certification of the PEFC standard and how these motivations vary depending on the characteristics of the companies. Findings reveal that the most valued motivations by this order are related to attracting customer attention, the improvement of companies’ corporate image, the sensitivity to environmental problems and the increase of the competitiveness of the company. Some of the motivations are significantly influenced by the characteristics of the companies, but only the export level has a significative influence (negative) on all the characteristics of the moral mechanism. The implications of the findings can help to identify and characterize the different clusters that exist among certified companies in the Spanish forestry sector. This information can be useful for managers and policy makers to better understand the specific reasons for each conglomerate of companies when opting for certification. •Forest certification drivers may be divided into five main mechanisms.•The main external drivers are “access new markets” and “improve corporate image”.•The main internal drivers are related to ethical or moral aspects.•These motivations vary according to the characteristics of the companies.