This paper addresses the adaptability and ability of three institutional actors of European securitythe EU, the NATO, and the OSCE - to properly respond to security challenges facing Europe, especially those existing at the non-state level. The position, status, nature and functions, and the relations within and between the key institutional actors of European security are considered within the study of international relations. Weaknesses in their operation have been identified, which are of a structural nature, but also a consequence of the international environment. In the EU, it is possible to identify a wide range of security policies, different developments and efficiencies. As a "civil force", the EU addresses security challenges using civil, political and economic instruments, focusing on the stability of its immediate environment. However, in order to play the role of a global security actor, the EU must build an autonomous security identity, which is, for now, an unsolvable problem. The NATO continues to be the personification of hard, military power in the face of security challenges, which does not sufficiently guarantee its security, and often means breaching the security of other countries. The OSCE, like NATO, is a relic of the past and its basic quality is diplomatic inclusiveness. It is an organization of "displaced" political power, without the necessary authority. The weaknesses of these three institutional actors, as well as the complexity of international relations, require a far higher level of political, functional and operational adaptability in order to understand and address the existing security challenges.