Police say as many as eight vehicles were involved in a pile up, just south of Ballaugh Bridge at lunchtime today.
At least one person has serious injuries and was airlifted to hospital.
It's understood motorbikes and cars were involved in the incident.
The stretch of the TT course from Douglas Road Corner, Kirk Michael to Ballaugh Bridge has been closed to traffic since just after midday, and will remain so until 6pm at the earliest.
'No change to hand baggage policy' says Steam Packet
Follows claims of new restrictions for foot passengers
Jail for man who tried to gouge a police officer's eyes out
35-year-old said he knew he'd be jailed so 'might as well make it worthwhile'
Response to census "exceptionally good" so far, says minister
Ashford says more than half of returns already received
Rushen MHK calls for progress on 20mph zones in south
Former DoI minister claims constituents still want to see limits reduced
Man caught with indecent images of children spared jail
39-year-old handed suspended sentence