Dozens of demonstrators gathered at the embassy in Princes Gate, Knightsbridge, London, on Sunday afternoon.
It comes as protests in Iranian cities have spread across the world, sparked by the death of 22-year-old Mahsa Amini in custody after being detained by Iranian morality police.
Angry protesters could be seen shouting and pushing against officers who had formed a line in front of the embassy.
Crowds chanted “Death to the Islamic Republic” and waved Iran’s former national flag from before 1979.
Footage shared online also showed violent altercations breaking out among those in the crowd.
One particular clip shows two officers wrestling a protester to the ground who appears to have broken through the police line.
Elsewhere, riot police could be seen trying to clear protesters off the road near Marble Arch.
Scotland Yard said several police officers were injured during the protests, although none are thought to be seriously hurt.
The force said the crowd showed “substantial group intent on causing disorder”, as protesters beached the police lines and threw missiles at officers.
Five people had been arrested on suspicion of violent disorder offences, the force said.
“A significant policing presence will remain in and around the area to monitor the situation,” the Met Police said.
By 7.30pm, the protesters had been cleared from the area outside the Iranian embassy, but handful of police officers remained outside the building.
There was little sign of the scenes from earlier in the day, except for a few battered protest posters.
A photo of Mahsa Amini could be seen on one poster, while another said “stop execution in Iran”.
It comes after Iran’s foreign ministry said on Sunday it had summoned Britain’s ambassador Simon Shercliff over what it described as a hostile atmosphere created by London-based Farsi language media outlets.