An anchor assembly for walls comprises a toggle member and a strap member pivotally mounted together, and a locking member. In a first position thereof, the toggle member is aligned with the strap member for insertion through the wall, whereas in a second position thereof, the toggle member extends behind the wall at an angle relative to the strap member which extends from the toggle member through the hole in the wall. The locking member is adapted to be displaced along the strap member until it engages the wall and to be locked on the strap member to prevent the locking member from displacing away from the toggle member. Therefore, the locking member and the toggle member are connected by the strap member and imprison the wall by abutting respectively the visible and hidden sides thereof. A fastener introduced through the locking member and the wall threadably engages an opening defined in the toggle member.