Companies are burdened under information flow overload. The knowledge maps can support the knowledge workers and decision makers in this situation. Knowledge map as a term has been used with various meaning in several different scientific communities: not only in knowledge management, but also in education studies, in organization studies, in decision analysis, in artificial intelligence etc. To generalize the variety of the definitions (e.g. Eppler or Leibovitz) one can use the term of knowledge map as a description of the sources, flows, constraints and sinks of knowledge within the organisation. The current study considers knowledge maps from knowledge management perspective and is devoted to the generalising the numerous scattered knowledge mapping research and practices. It aims to identify and generalize the contents of knowledge maps – what are the main concepts, which are represented in knowledge maps, and relationships between them. The discussed research results in an ontology (or conceptual model, as it was defined by Gruber) for knowledge maps. Existing types of knowledge maps are associated with fragments of this ontology, so typical views and templates will are also highlighted. Such an ontology may help to select the necessary elements for knowledge mapping in specific company and situation. The research methodology is based on literature review, semantic analysis and ontological engineering. The paper helps to clarify the content of knowledge maps, its’ meaning and possible components. It provides building blocks for creating company-specific knowledge mapping templates and practice.