They are not "the Taliban" that the U.S. forces have been at war with in Afghanistan, according to Raza Rumi, director of policy and programs at the Jinnah Institute, a Pakistani think tank. But that they adopted the name "Taliban" is no coincidence.
The group is very closely linked with its namesake in Afghanistan as well as with al Qaeda. It shares its religious extremist ideology -- but is its own distinct group.
The TTP also has a different goal, but its tactics are the same, says the analyst.
"Their primary target is the Pakistani state and its military," he says. "It resents the fact that it (Pakistan) has an alliance with the West, and it wants Sharia to be imposed in Pakistan."
Another terrorism analyst notes that "there is a shared heritage between the two groups."
"The Pakistani Taliban emerged as a power alongside the Taliban as a kind of network of support," says Matthew Henman of IHS Jane's Terrorism and Insurgency Centre.
During the Soviet occupation of Afghanistan, fighters from Pakistan crossed over the border to fight. They retained close relations with the Taliban after returning home, Rumi says.
There are other militant groups in Pakistan's tribal region not under the umbrella of the TTP, who support the Taliban but do not pursue Tehrik-i-Taliban's goals of replacing the Pakistani state with an Islamist one.
READ MORE: Taliban school attack: What do the militants want?
Where do the TTP's roots lie?
Pakistan's army began hunting various militant groups in the semi-autonomous regions along Pakistan's border with Afghanistan, known as the Federally Administered Tribal Areas (FATA), in 2002.
In reaction, militant "supporters of the Afghan Taliban in the tribal areas transitioned into a mainstream Taliban force of their own," according to the Council on Foreign Relations.
In 2007, like-minded militias in Pakistan's tribal region came together under the command of Baitullah Mehsud, who was killed in a U.S. drone strike in 2009.
As a result of its beginnings, Tehrik-i-Taliban are not a unified fighting force but a coordinated coalition of militias.
"Since its formation, the TTP have been dominated by one tribe," Henman says. "That is the Mehsud tribe." When Baitullah Mehsud died, factions competed for Tehrik-i-Taliban's leadership.
Who is their current leader?
Baitullah's successor, Hakimullah Mehsud, was killed in a U.S. drone strike in November 2013, setting off a power struggle among top commanders of the TTP that led to violent clashes in which dozens of people were killed.
Appointed by a tribal council, Mullah Fazlullah has stood at the helm of the TPP since Mehsud's death. He hails from the country's Swat valley and is the first TTP leader who is not a Mehsud. He has struggled to contain internal discord among the group's factions, especially those within the Mehsud tribe, which makes up the majority of the TTP.
The militant groups control different regions within the tribal areas and often have different agendas and political objectives. The factions don't always speak with one voice, although it is widely believed they now recognize Mullah Fazlullah as their leader.
The TTP may have started in the tribal regions, but have since expanded their network.
They are "not just guys hiding in mountains or caves," Rumi explains. They maintain loose factions spread out as far as Punjab province.
"They have also been joined by criminal gangs" to raise money through kidnappings and extortion. But the TTP have maintained the coalition nature of their roots, which leads to internal strife.
The TTP's opposition to the government and its allies, particularly the United States, has galvanized them beyond their differences.
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