The men, aged between 25 and 32, are being detained on suspicion of commission, preparation or instigation of an act of terrorism in the UK.
The investigation, involving MI5, is reportedly linked to suspected Islamist between extremism.
The men were taken into custody by unarmed police in the Moseley, Sparkbrook, Sparkhill, Ward End and Balsall Heath areas of Birmingham at 11.30 am on Sunday and 1.00 am today (Monday).
A 22-year old woman has also been arrested on suspicion of failing to disclose information contrary to the Terrorism Act of 2000.
Specialist teams are searching the homes of those arrested, as well as seven other properties in Birmingham – six domestic and one commercial.