The paper aims to identify, describe and analyse knowledge risks organisations might face and based on this, proposes a taxonomy of knowledge risks. To achieve this goal, a literature review was conducted. After the analysis of the existing material, it was possible to divide knowledge risks into two categories: Internal (originating from the inside of the organisation) and external (originating from the outside of the organisation). Some of the presented knowledge risks appear to have an incidental character (e.g., knowledge spillover, knowledge leakage or knowledge waste), while others are of a continued nature (e.g., knowledge attrition or risks connected with knowledge work). Our study is not only timely but also relevant for initiating increased and rigorous research activities in the field of knowledge risks. The proposed taxonomy will also help organisations in concentrating on their crucial knowledge and in finding ways to prevent or reduce these risks.