The incident is the third cyclist death involving an HGV to take place in London this year and the fourth cyclist fatality in 2021.
Police were called by the London Ambulance Service at 4pm on Tuesday to reports of a lorry in collision with a cyclist on High Street at the junction with Furness Road, near Willesden Junction overground station.
But despite the efforts of the emergency services, the man was pronounced dead at the scene.
The driver had failed to stop and officers have since made contact with them, the Met said.
The death comes just months after a male cyclist died in a collision involving another HGV at the junction of the A13 and Marsh Way on January 14.
A male cyclist aged 65 died in collision with a van on March 9 on Bourne Road in Bexley.
HGVs were involved in 15 per cent of fatal crashes in the capital between 2018 and 2020, despite making up just three per cent of vehicle traffic, according to TfL.
This includes 41 per cent of collisions where a cyclist was killed, and 19 per cent of those with a pedestrian fatality.