It had previously been rumoured that the 84-year-old Pope would attend the climate conference.
However, the Vatican announced on Friday its delegation would be led by Cardinal Parolin, its secretary of state.
Pope Francis was expected to be among around 120 world leaders due to attend the event.
Dignitaries will also be in Edinburgh as a result of the climate conference. The Pope, Joe Biden and the Queen will all base themselves in Edinburgh during Cop26.
The news comes as the UK will host the 26th UN Climate Change Conference of the Parties (COP26) in Glasgow on October 31 to November 12.
A papal spokesman said: "Responding to journalists' questions about the Holy See's participation in the session of @COP26, scheduled to take place in #Glasgow from October 31 to November 12, the Delegation will be led by His Eminence Pietro Parolin, Secretary of State of His Holiness.”
Pope Francis met alongside other religious leaders and scientists from around the world in the Vatican on Monday, to take a common stand for the protection of the environment.
During the “Faith and Science: Towards COP26” meeting, the Pope noted that COP26 “represents an urgent summons to provide effective responses to the unprecedented ecological crisis and the crisis of values that we are presently experiencing, and in this way to offer concrete hope to future generations.”