This paper aims to improve the applicability and relevance of contingency theory research in the field of Operations Management. Based on the results of previous studies, we have identified a systemsbased single definition of organisation types that could describe the fit between organisational environment and organisational structure. This definition of organisation type, which we call an 'organisational system', regards the organisation as an integrated whole instead of as a sum of its parts and can help to better classify organisations in order to identify fits between organisation types and emerging practices in Operations Management.