The Guadalcanal Campaign, also known as the Battle of Guadalcanal and codenamed Operation Watchtower by Allied forces, was a military campaign fought between August 7, 1942 and February 9, 1943 on and around the island of Guadalcanal in the Pacific theatre of World War II. It was the first major offensive by Allied forces against the Empire of Japan.

On August 7, 1942, Allied forces, predominantly American, landed on the islands of Guadalcanal, Tulagi, and Florida in the southern Solomon Islands with the objective of denying their use by the Japanese to threaten the supply and communication routes between the U.S., Australia, and New Zealand. The Allies also intended to use Guadalcanal and Tulagi as bases to support a campaign to eventually capture or neutralize the major Japanese base at Rabaul on New Britain. The Allies overwhelmed the outnumbered Japanese defenders, who had occupied the islands since May 1942, and captured Tulagi and Florida, as well as an airfield (later named Henderson Field) that was under construction on Guadalcanal. Powerful U.S. naval forces supported the landings.