Murtala Nyako denies the allegations, and his party, the All Progressives Congress (APC) vowed to fight the move in court.
Nyako's political problems began last year when he was among a group of powerful governors that quit President Goodluck Jonathan's ruling Peoples Democratic Party (PDP) to join the opposition APC.
He fiercely criticised Jonathan's decision to include Adamawa in the states placed under emergency rule in May 2013.
He argued that Adamawa had been relatively lightly touched by Boko Haram violence and claimed the state of emergency was imposed there as an attempt by Jonathan to sideline a rival.
More From This Section
As Nyako's dispute with Jonathan escalated, the 25-member Adamawa state assembly, which is dominated by the PDP, launch a corruption probe, including into claims that the governor lavishly spent public funds while hosting senior APC leader Muhammadu Buhari.
"The process that led to that (impeachment) is unfair and will be challenged in court," APC spokesman Lai Mohammed told AFP.
The deputy governor, Bala James Ngillari, next in line to run the state, resigned before the impeachment motion was approved.
Nigeria's state governors have a significant amount of autonomy on areas including education and infrastructure spending, and each by law is entitled to a portion of the revenue from Africa's biggest oil industry.