The images all relate to separate incidents that occurred in different parts of the city between March and July.
They are not believed to be connected, the force said.
The incidents include a 22-year-old woman who was sexually assaulted on the 149 bus on Sunday, May 30 which is reported to have happened around 10.30pm between Edmonton and Stoke Newington.
A 30-year-old man was also sexually assaulted on the N207 bus on Tuesday, July 27, after 1.45pm between Uxbridge and Hayes.
The third assault took place on Sunday, June 27 after a man indecently exposed himself at a bus stop in Sutton at around 5.45pm.
Police are also appealing for information after an 18-year-old man was sexually assaulted on a U4 bus on Friday, June 11 at 3.20pm.
In a fifth incident, a 16-year-old girl was sexually assaulted on a 102 bus on Thursday, March 25 near Green Lanes.
Detective Superintendent Christina Jessah, of the Met’s Roads and Transport Policing Command, said: “Ensuring that buses remain a safe and open space for all is vital.
“I stress that sexual assaults of this nature continue to be very rare but in the cases when it does happen we remain dedicated to supporting victims and identifying and prosecuting those responsible.
“The technology and investigative tactics available to officers are very strong but information provided by the public also has a key role to play.”
Detective Jessah said she encourages anyone who is a victim of sexual offences or who witnesses an offence taking place “to contact police so we can track down the perpetrator”.
She added: “These despicable acts are unacceptable, will not be tolerated and have no place on our bus networks or within our communities. We will continue our commitment to make bus routes safe for those travelling.”
Anyone with information is asked to contact police by calling 101, or tweeting @MetCC, providing the CAD reference for the relevant image.