The multi-storied masonry “Gopuram” or the ceremonial entrance gateway, an ubiquitous structure in a South Indian temple, was a feature introduced circa 14 ^th c. AD in order to confer architectural status to structurally insignificant ancient shrines. The gopurams of the Meenakshi Temple in Madurai (1600 AD), the Ranganathaswamy Temple in Srirangam (17 ^th c. AD) and the Ekambareswar Temple in Kancheepuram (16 ^th c. AD), 52 m, 72 m and 59 m tall, respectively, are representative of the highly evolved Dravidian temple architecture. The current research is an attempt to understand the structural behaviour of the gopuram with a focus on a centuries-old incomplete structure in the town of Thiruvellarai in Tamil Nadu. The paper presents outcomes of detailed field and laboratory investigations on the sub-structure, the superstructure and structural materials of the gopuram, that provide insight into the structural configuration of the gopuram. It then examines the structural response to gravity and lateral forces, through non-linear finite element models of the structure. One of the significant aspects studied is the role of the core masonry in the structural response of the multi-leaf masonry structure of the gopuram. In addition the role of floor diaphragms in the structural stability of the gopuram is investigated. The outcome of the study is expected to provide important insights to the reasons for structural distress and collapse of such structures, particularly the Vijayagopuram at Srikalahasti in Andhra Pradesh in South India that collapsed in May 2010.