第十次十字軍（だいじゅうじじゅうじぐん、Tenth Crusade）は、アメリカのジョージ・W・ブッシュを大統領とする政権（ブッシュ政権）の行った、アフガニスタン紛争やイラク戦争などの軍事行動をいう。歴史的な意味での十字軍（数え方に見解の違いはあるが、第9回まで行われたとされている）になぞらえた名称である。

十字軍という言葉の使用 
2001年9月11日のアメリカ同時多発テロ事件についてブッシュが国家哀悼日（:en:National day of mourning）、「this crusade, this war on terrorism」（この十字軍、この対テロ戦争は―）と述べた 。この言葉は中東からは批判されたが、米国では以前から使われている言葉であり、例えば第二次世界大戦時にドワイト・D・アイゼンハワーも欧州に上陸・侵攻する日、D-デイの言明に際してThe Great Crusade（偉大な聖戦）という言葉を使っている 。

第十次十字軍 
2002年9月7日、雑誌「カウンターパンチ」にコラムニストのアレグザンダー・コバーンの記事「第十次十字軍」が掲載された。

2003年12月4日、ニューズデー誌に政治評論家のジェームズ・ピンカートンの記事が掲載された。その中で同氏はコウバーンの発言を踏襲して第十二次十字軍と（Twelfth Crusade）と呼んだ。アメリカの侵攻を十字軍という単語で表すのは一般にピンカートンに始まるものとされる。

他の用例 
 2001年5月7日に刊行されたチュニジアでの英語を扱った論文. English in Carthage; or, the "Tenth Crusade" Mongi Bahloul, University of Sfax for the South, Tunisia.
 クリストファー・ハイド（Christopher Hyde）の小説. Tenth Crusade. 1983: Boston, MA. Houghton Mifflin. 270 pages.

引用 
US President George W. Bush, from a press conference upon arrival at the South Lawn of the White House, September 16, 2001.  "We need to go back to work tomorrow and we will.  But we need to be alert to the fact that these evil-doers still exist.  We haven't seen this kind of barbarism in a long period of time.  No one could have conceivably imagined suicide bombers burrowing into our society and then emerging all in the same day to fly their aircraft — fly U.S. aircraft into buildings full of innocent people — and show no remorse.  This is a new kind of — a new kind of evil.  And we understand. And the American people are beginning to understand. This crusade, this war on terrorism is going to take a while.  And the American people must be patient.  I'm going to be patient. But I can assure the American people I am determined, I'm not going to be distracted, I will keep my focus to make sure that not only are these brought to justice, but anybody who's been associated will be brought to justice.  Those who harbor terrorists will be brought to justice.  It is time for us to win the first war of the 21st century decisively, so that our children and our grandchildren can live peacefully into the 21st century." 

US President George W. Bush, from a rally for the troops in Alaska, February 16, 2002.  "I want to tell you something, we've got no better friends than Canada.  (Applause.) They stand with us in this incredibly important crusade to defend freedom, this campaign to do what is right for our children and our grandchildren."

Alexander Cockburn, "The Tenth Crusade," Counterpunch, September 7, 2002.  "Islamic fanatics flew those planes a year ago and here we are with a terrifying alliance of Judaeo-Christian fanatics, conjoined in their dreams of the recovery of the Holy Lands of the West Bank, Judaea and Samaria. War on Terror? It's back to the late thirteenth century, picking up where Prince Edward left off with his ninth crusade after St Louis had died in Tunis with the word Jerusalem on his lips."

James Pinkerton, "Century In, Century Out - It's Crusade Time," Newsday, December 4, 2003.  "And now, in 2003, the Americans, the Twelfth Crusaders. The West is no longer 'Christendom,' but we, as first cousins to the Europeans, retain the old faith and bring new kinds of idealism, such as democracy and human rights. But the Crusader spirit is still there; it's still about bringing civilization and salvation of a backward people. As the born-again George W. Bush says, 'This is about good vs. evil.'"