In this dissertation, I investigate the history of Croatian museum theory and practice during and after the era of socialist Yugoslavia. In particular, I explore the development of socialist museology, the extent to which these ideas were implemented in Croatian history museum spaces, the role these history museums played in the development of what I term “Croat Yugoslavism,” and likewise, the extent to which they participated in its destruction in the post-socialist context. I argue firstly that Croatian museology developed into a robust and critically engaged academic study during the socialist era that in many ways kept up with—if not outpaced—advancements in Western museology during the same period. At the same time, as both products and producers of the predominant state mythology of socialist Yugoslavism, I argue that Croatian history museums played a key role in the negotiation of socialist Yugoslav identity and ethnic Croat identity. Far from mere mouthpieces for the socialist Yugoslav state, I contend that Croatian history museums were complex, living institutions that contained a great deal of variety depending on their thematic and temporal scope. As such, I engage with two related conversations: the ongoing process of nationalization in the context of postwar communism, and the role of socialist countries in the development of modern museology. I join these conversations, on the one hand, by analyzing Croatian museological literature in the context of postwar international museology. Specifically, I investigate how Croatian museology developed within the parameters of postwar museology, and crucially, the extent to which it helped establish a new orthodoxy of public oriented museology. On the other hand, I explore a range of Croatian history museums, from Party-line revolutionary and memorial museums to locally oriented regional and city museums. In doing so, I demonstrate the extent to which Croatian history museums played a role in the overall construction of Croat Yugoslavism, and in the process, shed light on the specific areas of Croatian history the Yugoslav state was most interested in harnessing.