The RNLI team was making its way past Kew Gardens at around 11.45am on Monday (September 7), when a member spotted a black dog which was moments away from sliding back down into the water.
The crew quickly reached the dog, named Pepper, and brought him to safety on board the lifeboat before reuniting him with his relieved owner.
RNLI helmsman Glen Monroe said: "It was very fortunate that we were passing by, as Pepper was unable to save himself and the owner had no way of reaching him.
"We carry out a number of dog rescues each year as we are always concerned that the owners may try to enter the river to retrieve their dogs, often putting themselves at more at risk than their pets."
Jan Rushton was out walking Pepper when he slipped off the edge of the path, down the concrete slope and into the water.
He was trapped some 3m below the distraught owner who was laying on the ground desperately trying to reach him.
Pepper managed to scramble 1m up the wall, only to find himself unable to make his way up or down as he balanced on the slope.
Ms Rushton, thanked the crew, adding: "I’m sure Pepper would have fallen back into the water and not been able to make it out if the crew hadn't come to help when they did.
"Thank you to the RNLI for saving my dog."
If your pet enters the water, never attempt to follow it. Instead, find a safe place on the river bank and call your dog towards you. Dogs should always be kept on a lead if they’re close to fast flowing rivers. If your pet is in danger, call 999 and ask for the Coastguard.