Human movement has long driven architectural innovation. Through travel, migration, and conflict, people transmit ideas across regions, fostering the fusion of diverse design traditions. A notable result of such exchange is the eclecticism movement, which gained prominence from the mid-1800s to WWI. Eclecticism combined historical elements from different cultures with local styles, forming a new creative synthesis. Although dismissed during the modernist era for lacking coherence and authenticity, eclecticism continues to manifest in contemporary architecture in diverse forms shaped by nuanced engagements with history, and the dynamics between globalization and regionalism. A notable example can be seen in contemporary mosque architecture. Eclecticism was not an inherent stage in its historical evolution, yet contemporary mosque design increasingly blends diverse stylistic influences and innovative formal languages with traditional conventions in a pursuit of a modern architectural identity. The resultant fusions have sparked debates around loss of cultural identity, lack of coherence, authenticity, and contextual sensitivity—echoing similar concerns raised about 19th-century eclectic architecture. Against this backdrop, this chapter investigates the intricate relationship between the cross-cultural migration of architectural ideas and the emergence of eclecticism in mosque architecture. The study traces historical instances of cross-cultural influences in mosque design, highlighting how the colonial period served as a significant catalyst for introducing eclectic approaches to its architecture. The chapter follows by identifying various forms of the resurgence of eclecticism in contemporary mosques, concluding with speculations on the potential of AI-generated imagery to shape a new form of architectural eclecticism.