Enterprise Application Integration (EAI) plays an important role by linking heterogeneous applications in order to support business processes within and across organizations. In this context, semantic conflicts often arise and have to be dealt with to ensure successful interoperation. In recent years, many EAI initiatives have aimed at addressing semantic interoperability challenges by employing ontologies in various ways. This paper aims to reveal, through a systematic review method, some aspects associated with semantic EAI initiatives and the adoption of ontologies by them, namely: (i) the business application domains in which these initiatives have been conducted; (ii) the focus of the initiatives regarding integration layers (data, message/service, and process); (iii) the adoption of ontologies by EAI research along the years; and (iv) the characteristics of these ontologies. We provide a panorama of these aspects and identify gaps and trends that may guide further research.