Periodontal disease is a chronic inflammatory condition of the tooth-supporting tissues in which the host inflammatory response drives the destruction of alveolar bone and periodontal attachment. The Hippo signaling pathway is a conserved regulatory network that controls cell proliferation, apoptosis, and bone homeostasis, but its role in human periodontal disease remains unknown. This observational, case-control study compared the levels of Hippo signaling pathway proteins (YAP, TAZ, MST1, TEAD, LATS1, MAP4K4), the anti-apoptotic protein BCL-2, and the bone metabolism marker alkaline phosphatase (ALP) in gingival crevicular fluid across 75 systemically healthy participants grouped as periodontally healthy, gingivitis, or stage 3 grade B periodontitis. The aim was to determine whether these proteins are differentially expressed across periodontal health and disease states and whether they correlate with markers of apoptosis and bone metabolism.