Crews were called to Clayworth Court on the Bellamy Road estate in the early hours of this morning to extinguish a house fire.
When they arrived firefighters found three houses alight and used breathing apparatus, hose and main jets to put out the blaze.
A spokesman said residents had all been accounted for and added: "Fire crews arrived on the scene from Mansfield, Ashfield, Blidworth, London Road, Hucknall, Edwinstowe and Stapleford fire stations.
"Nottinghamshire Police have put up a cordon on Bellamy Road, and the ambulance service also attended.
"Crews used six pumps and an aerial ladder platform to put out the fire, and crews were dampening down at 6.30am this morning.
A spokesman for Nottinghamshire Police said were no reports of anyone trapped and two people were taken to hospital for smoke inhalation. They have since been discharged.
A scene remains in place whilst detectives investigate the cause and work with Nottinghamshire Fire and Rescue Service.
Detective Sergeant Matt Scott said: "We were called in the early hours of this morning to assist the local fire service to evacuate occupants from seven properties safely.
“We are keeping an open mind at this stage and we are keen to speak to anyone who may have witnessed the incident or seen someone they don’t know enter or leave the building.
"We are now appealing to anyone who saw anything suspicious in the area at that time to ring 101, quoting incident number 27 of 6 July 2020."