The NS1 (nonstructural protein 1) antibody is primarily associated with research and diagnostic applications targeting flaviviruses, such as dengue, Zika, and West Nile viruses. NS1 is a conserved glycoprotein critical for viral replication and immune evasion. During infection, NS1 is secreted by host cells and circulates in the bloodstream, contributing to pathogenesis by disrupting complement activation and suppressing interferon responses. Antibodies against NS1 have become valuable tools for both basic research and clinical purposes. In diagnostics, NS1-specific antibodies are used in ELISA and rapid tests to detect early-stage infections, as NS1 appears before seroconversion. Therapeutically, NS1-targeting antibodies are explored for their potential to neutralize NS1's immune-modulatory effects or enhance immune clearance. However, challenges remain, including cross-reactivity between NS1 proteins of different flaviviruses, which complicates specific diagnosis in regions with co-circulating viruses. Additionally, the role of anti-NS1 antibodies in antibody-dependent enhancement (ADE) of infection, particularly in dengue, requires careful evaluation. Research continues to optimize NS1 antibody specificity, improve diagnostic accuracy, and assess their safety in therapeutic contexts. Understanding NS1-antibody interactions remains pivotal for developing targeted antiviral strategies and vaccines against globally significant flaviviruses.