AfPak (also spelled Af-Pak) was a neologism used within United States foreign policy circles to designate Afghanistan and Pakistan as a single theater of operations. Introduced in 2008, the neologism reflected the policy approach that was introduced by the Obama administration, which regarded the region comprising the Asian countries of Afghanistan and Pakistan as having a singular dominant political and military situation that required a joint policy in their global war on terrorism.

Following sharp criticism from Pakistan, which condemned the hyphenation of the country's geopolitics with Afghanistan, the U.S. government stopped using the term in 2010. In 2017, the Trump administration expanded its Afghanistan policy to a regional South Asia strategy, which sought continued counter-terrorism cooperation with Pakistan, but envisaged a greater economic role for India in Afghanistan; the new approach was dubbed "AfPakIndia".

British writer Michael Quinion writes that the term began appearing in newspaper articles in February 2009. The term was popularized and possibly coined by Richard Holbrooke, the Obama administration's Special Representative for Afghanistan and Pakistan. In March 2008 (a year before he assumed the post), Holbrooke explained the motivation behind the term:

First of all, we often call the problem AfPak, as in Afghanistan–Pakistan. This is not just an effort to save eight syllables. It is an attempt to indicate and imprint in our DNA the fact that there is one theatre of war, straddling an ill-defined border, the Durand Line, and that on the western side of that border, NATO and other forces are able to operate. On the eastern side, it's the sovereign territory of Pakistan. But it is on the eastern side of this ill-defined border that the international terrorist movement is located.

According to the U.S. government, the common policy objective was to disrupt, dismantle, and prevent al-Qaeda and its affiliates from having a safe haven from which it can continue to operate and plot attacks against the U.S. and its allies. This policy decision represented a shift from previous ways of thinking about Afghanistan as an independent problem that required a military solution.^{[citation needed]} The AfPak strategy was an attempt to win the “hearts and minds” of both Afghans and Pakistanis.^{[citation needed]}

In 2009, the National Security Advisor under the Barack Obama administration, James L. Jones, proposed reversing the term to "PakAf"; this proposal was met with staunch resistance in Pakistan due to its supposed suggestion that Pakistan was the primary source of difficulty in the war on terror, according to Bob Woodward in his 2010 non-fiction book Obama's Wars.

The term "AfPak" has entered the lexicon of geopolitics, and its usage implies that the primary fronts for the global war on terrorism were in Afghanistan and Pakistan at the time. It has reinforced the message that the threat to United States from pro-terrorist activities masquerading as Islamic religious policy and the resulting infrastructure of fear and disarray in the two countries are intertwined.

Official use of the term within the Obama administration has been echoed by the media, as in The Washington Post series The AfPak War and The Af-Pak Channel, a joint project of the New America Foundation and Foreign Policy magazine that was launched in August 2009.