The interferon-induced transmembrane protein 3 (IFITM3) is a critical component of the innate immune system, known for its role in restricting viral infections by inhibiting the entry of pathogens such as influenza, dengue, Zika, and SARS-CoV-2 into host cells. It is part of the IFITM family, which is induced by interferons in response to viral threats. IFITM3 localizes to endolysosomal membranes, where it disrupts viral envelope fusion with host membranes, effectively blocking infection. Antibodies targeting IFITM3 are essential tools for studying its expression, subcellular distribution, and functional mechanisms in both physiological and pathological contexts. These antibodies enable techniques like Western blotting, immunofluorescence, and flow cytometry, aiding research into its antiviral activity, regulation, and interactions with viral or host proteins. IFITM3 has garnered significant attention due to its genetic association with disease severity; for example, the rs12252-C variant is linked to heightened susceptibility to severe influenza in certain populations. Additionally, dysregulation of IFITM3 has been implicated in cancer progression and other inflammatory conditions, expanding its relevance beyond virology. Reliable IFITM3 antibodies are crucial for elucidating its dual roles in infection defense and potential pathological processes, making them indispensable in immunology, virology, and biomedical research.