Information warfare (IW) is the battlespace use and management of information and communication technology (ICT) in pursuit of a competitive advantage over an opponent. It is different from cyberwarfare that attacks computers, software, and command control systems. Information warfare is the manipulation of information trusted by a target without the target's awareness so that the target will make decisions against their interest but in the interest of the one conducting information warfare. As a result, it is not clear when information warfare begins, ends, and how strong or destructive it is.

Information warfare may involve the collection of tactical information, assurance(s) that one's information is valid, spreading of propaganda or disinformation to demoralize or manipulate the enemy and the public, undermining the quality of the opposing force's information, and denial of information-collection opportunities to opposing forces. Information warfare is closely linked to psychological warfare.

Information warfare has been described as "the use of information to achieve our national objectives." According to NATO, "Information war is an operation conducted in order to gain an information advantage over the opponent." The term has existed at least since 1970, when Dale Minor, a reporter, published The Information War a book about propaganda and news manipulation during the Vietnam War era., although its current usage as a military capability dates from 1976, when Thomas P. Rona, than a Boeing Company engineer, referred to "information war" in a company monograph prepared for the Office of Net Assessment.

Information warfare can take many forms:

The United States Air Force has had Information Warfare Squadrons since the 1980s. In fact, the official mission of the U.S. Air Force is now "To fly, fight and win... in air, space and cyberspace", with the latter referring to its information warfare role.

As the U.S. Air Force often risks aircraft and aircrews to attack strategic enemy communications targets, remotely disabling such targets using software and other means can provide a safer alternative. In addition, disabling such networks electronically (instead of explosively) also allows them to be quickly re-enabled after the enemy territory is occupied. Similarly, counter-information warfare units are employed to deny such capability to the enemy. The first application of these techniques was used against Iraqi communications networks in the Gulf War.

Also during the Gulf War, Dutch hackers allegedly stole information about U.S. troop movements from U.S. Defense Department computers and tried to sell it to the Iraqis, who thought it was a hoax and turned it down. In January 1999, U.S. Air Intelligence computers were hit by a coordinated attack (Moonlight Maze), part of which came from a Russian mainframe. This could not be confirmed as a Russian cyber attack due to non-attribution – the principle that online identity may not serve as proof of real-world identity.

Some militaries are now employing the use of iPhones to upload data and information gathered by drones in the same area.