Critical infrastructure, including energy grids, public utilities, transportation networks, telecommunications systems, financial services, etc., is highly susceptible to hybrid threats due to its interconnected nature and reliance on digital technology. Disruptions to critical infrastructure can have cascading effects on society, economy, environment, and national security overall. The fight against hybrid threats and the protection of critical infrastructure are of paramount importance in the European Union (EU), because these threats, through the aforementioned cascading effects, can destabilize economies, and erode public trust. Ensuring the resilience of critical infrastructure represents a vital element for safeguarding public safety and social well-being. In this sense, enhancing resilience and diversifying supply chains are key strategies for reducing reliance on external sources. With no less importance is the fact that addressing hybrid threats and protecting critical infrastructure require cross-border collaboration and information sharing both among EU member states and accessing countries like the Republic of Serbia, prominent international partners (like ISO), and relevant stakeholders (like NATO). In the Republic of Serbia, a formal legislative framework for critical infrastructure protection was established by the adoption of the Law on critical infrastructure in 2018. With a significant reference to international experiences, in the Republic of Serbia, there are still many challenges in the field of protection of critical infrastructure, especially from hybrid threats. In this sense, the goal of this paper is to present the possibility of improving the resilience of critical infrastructure through the standardization of management activities, the operationalization and objectification of the sources of priority activities using the multi-criteria decision-making method, and the integration of the requirements of various interested parties through a systems approach. The main conclusion and contribution of the paper refer to the need for more intensive harmonization of practice in the Republic of Serbia with that in the EU.