The protest was one of a string of protests that included highly disruptive blockades of UK transport networks.
Former Team GB athlete Stott, 43, and the other activists were acquitted after a judge ruled the part of the tanker they glued themselves to was not a motor vehicle.
The group had targeted a tanker belonging to Anglo-Dutch energy giant Shell as it left a petrol station in west London in April 2022, later having to be removed by police "de-bonding" experts.
They were each found not guilty of one count of tampering with a motor vehicle at trial in London.
Judge John Zani ruled the defendants had not bonded themselves to the vehicle itself but the trailer attached to it.
"On the basis of that there is no case to answer here in relation to any of the defendants and the cases against each of the five are dismissed," Zani said in court.
The court heard earlier that canoe slalom champion Stott and another activist climbed on top of the empty tanker as the driver attempted to drive it out of a petrol station.
The pair glued their hands to a bar on top of the tanker but were eventually bought down by police with a specialist crane and a special frame, and were then dragged away by officers.
"I am aware that my actions will cause anger to many people and I am prepared to be held accountable," Stott said at the time.
"But our government should also be held to account for its decisions which are destroying our planet's ability to support human civilisation."
Extinction Rebellion is a loosely linked network that originated in the UK in 2018.
It has pushed businesses and the government to take action on the climate crisis with eye-catching but non-violent acts of civil disobedience that have led to mass arrests - as well as some public anger - over the disruption caused to the lives of ordinary citizens.
Activists gained notoriety for blockading train lines, airports and roads, causing chaos for commuters.
Earlier this month, the network announced a temporary halt to public disruption in the UK as they seek broader support.
Stott won gold at the London 2012 Olympic Games in the Canoe Double Men's Slalom
