The implementation and use of environmental management systems (EMSs) depend on the perceived credibility of their certificates. This study aims to identify and describe factors influencing the importance of certification credibility of EMSs. This study discusses the significance of such systems to enterprise credibility by administering and analysing focus group interviews with 20 representatives from the production industry, education sector, certification bodies, and non-profit associations for environmental protection. The paper concludes that credibility of EMSs’ certification depends on the certifying companies, and poor-quality audits facilitate the possession of certification as well as the universality of using certified systems. The positive reception of certified EMSs in companies induces the widespread use of certificates, fashion, and credibility, which can be increased by publication of audit reports. These conclusions emphasise the importance of strict auditing and control systems for certifications.