Nymwars was a series of conflicts over policies that mandate that all users of certain internet communications platforms identify themselves using their legal names. The term is mostly associated with Google's name policies on Google+ and YouTube. Nymwars is a blend word composed from (pseudo)nym and wars. The name appears to have gained prominence as the hashtag "#nymwars" on Twitter.

Conflicts regarding Google+ began in July 2011 when the social networking site began enforcing its real-name-only policy by suspending the accounts of users it felt were not following the policy. Pseudonyms, nicknames, and non-standard real names (for example, mononyms or names that include scripts from multiple languages) were suspended. The issue was settled in July 2014 when Google announced that it was ending its real-name-only policy.

A predecessor to the Google+ conflict was Blizzard's RealID which, starting in July 2010, exposes the name on the player's credit card, and is mandatory to use some game features (cross-game chat) and was nearly made mandatory to post on discussion forums.

These issues have existed since the beginning of online identity, and are related to the alleged online disinhibition effect. The resulting discussions have raised many issues regarding naming, cultural sensitivity, public and private identity, privacy, and the role of social media in modern discourse. The debate has been covered widely in the press including Wired, The Atlantic, and The New York Times.

Google Plus was launched in late June 2011. At the time of launch, the site's user content and conduct policy stated, "To help fight spam and prevent fake profiles, use the name your friends, family or co-workers usually call you." Many users signed up using nicknames, handles, stage names, or other names by which they were commonly known, but which did not necessarily match the name on their government-issued ID.

The first suspensions for name-related reasons occurred in July 2011, and included Limor Fried's account, which included the name "LadyAda" (by which she is widely known), nerdcore rapper Doctor Popular, and LA Weekly and Los Angeles Times columnist A.V. Flox. Account suspensions over the following weeks included those who were using nicknames, handles, and pseudonyms; those whose legal names were unusual, including mononymous users; and some users who Google mistakenly believed were impersonating famous individuals, such as Facebook employee and Mozilla founder Blake Ross, and actor William Shatner.

Awareness of the issue grew rapidly, via Twitter, Google+ itself, and a variety of media outlets. By early August, the Electronic Frontier Foundation had posted "A Case for Pseudonymity" in response to the issue.

Google initially responded on 25 July when vice president Bradley Horowitz promised improvements to the suspension and enforcement process. On 17 August, Google implemented a "grace period" before suspension, and on 19 August, a "verified account" program for celebrities and high-profile users.