Behavioural Operational Research (BOR) is a young research ﬁeld in the area of Operational Research (OR). BOR emphasizes the inﬂuence of cognitive psychology for the use of quantitative methods as decision support and seeks to embed behavioural ﬁndings into OR. This is necessary as the interdisciplinary and real world application driven focus of OR appears to stand in an unbalanced relationship compared toitsmathematical-technicalresearch. Among other things, BOR tries to reduce this imbalance. However, it still has the problem of being a rarely well-deﬁned ﬁeld. Therefore, classiﬁcation of BOR and its main issues - on a meta-level - is just as important as the embedment of behavioural aspects into OR. This contribution presents BOR as a research ﬁeld within two areas of conﬂict, characterized by two dimensions and four theoretical constructs. For simplicity, each dimension concerns real world and model world aspects. Therein, application of OR methods faces the importance of fundamental research concerning these methods, and the postulate of rationality is challenged by behavioural scientists. Out of this new perspective - which will be introduced in detail - central points of BOR are depicted in a diﬀerent light. This ﬁnally leads to an extended classiﬁcation approach helping BOR to shape its proﬁle and to obtain more acceptance in the scientiﬁc community.