This paper deals with the transformation of the NATO alliance from a system of collective defense to a system of collective security with special emphasis on peace support missions. The changes that took place at the global level forced the NATO alliance to expand its tasks in order to ensure its presence in the international community. As part of this, the development of the Republic of Croatia will be shown from the recipient of aid during the war to the provider of aid shortly after independence. With the end of the war in Croatia and its independence, Croatia began to work intensively on approaching membership in international organizations. It is visible that the desire to expand the NATO alliance came from two sides. On the one hand, by establishing the Partnership for Peace, NATO tried to facilitate for potential members to enter the Alliance, and on the other hand, the countries tried to meet all the criteria by creating national strategic documents. In addition, Croatia tried to stand out through participation in peacekeeping missions. It is visible that Croatia already joined the peacekeeping mission in Afghanistan in 2003, although it became a full member of the NATO alliance in 2009. Since then, until today, the Republic of Croatia has participated in a series of missions and activities of the NATO alliance. Therefore, the paper tries to answer the question: What influenced the transformation of Croatia, which until 1995 was a recipient of security, into a provider of security within the peacekeeping missions of the NATO alliance? In order to find the answer, it was necessary to look at the environment at that time, the influence of the NATO alliance, but also the strategic documents that also influenced Croatia's position on the international level.