The World Health Organization has classified snakebite envenoming as one of the world’s most neglected tropical diseases, affecting millions of people each year. The only effective treatment for envenoming is traditional antivenom derived from the plasma of animals immunized with snake venom. Though these medicines have saved countless lives since their invention, they have several drawbacks, including a propensity to cause adverse reactions due to their non-human origin. The monocled cobra (Naja kaouthia) belongs to the Elapid family and is one of the most feared snakes in Southeast Asia. Its venom is highly neurotoxic, mainly deriving its toxicity from potent long-chain α-neurotoxins. α-cobratoxin belongs to this group of toxins, and it is the toxin with the highest abundance and medical relevance in N. kaouthia venom. We present the discovery and subsequent affinity maturation of a human monoclonal immunoglobulin G (IgG) antibody against α-cobratoxin using in vitro phage display technologies. The antibody was characterized through binding and receptor blocking assays, as well as its ability to neutralize the toxin in vitro using automated patch-clamp technology. These studies yielded an antibody with high binding affinity and in vitro neutralization potency. The findings translated well into the in vivo setting, where the antibody could neutralize N. kaouthia whole venom in a rodent model using intravenous administration of preincubated antibody and venom. These studies thus constitute the first report of a recombinant human IgG antibody able to neutralize the lethality of an animal venom by the intravenous route.