Two inmates climbed on to a prison roof in a stand-off lasting more than 13 hours.
The HMP Isle of Wight prisoners accessed the roof of the Albany building in Newport at about 14:00 BST on Tuesday.
The stand-off, said to be over parole issues, ended shortly before 03:45 BST.
A spokesman for the Ministry of Justice (MoJ) said officers resolved the situation "with no injuries to staff or prisoners".
Fire crews attended with an aerial ladder as a precaution.
The Prison Officers Association (POA) has called for a review of the jail's security and said the inmates were protesting over parole issues.
Mark Fairhurst of the POA said: "Prisoners gaining access to the roof shouldn't happen."
The MoJ said the incident was being investigated.