This thesis introduces and explains the position and role of the executive power, in Republic of Croatia in particular, its authority under ordinary circumstances, with special reference to its restrictions in extraordinary circumstances. Through a review of executive power restrictions in extraordinary circumstances according to the classical theory and the modern theory of terrorism, this thesis elaborates the origin and development of states of emergency, the means of their implementation, acceptance of said state of emergency as one of the legal ways to govern a democratic state and legal mechanisms and powers which executive power has sin its hands in emergency circumstances. This thesis elaborates Croatian executive power restricting system in extraordinary circumstances in particular, its restrictions activity in Croatian practice, during the time of Croatian War of Independence and post-war period, during a declared Covid-19 pandemic and in situations of emergence of economic and migrant crises.Last chapter of this thesis reviews once again on its most important parts, states and elaborates today's actualities and situations during the introduction of emergency states and presents the final recapitulation of the assigned theme.