Emergency services raced to the scene after the accident happened on the A14’s eastbound carriageway between junction 1 at Welford and junction 2 at Kelmarsh.
Two light good vehicles, two vans and a car collided at about 7.10am, said Northamptonshire Police.
No one was seriously injured.
Both eastbound lanes were shut as traffic queued back for about seven miles almost all the way to the M1.
The road is now believed to have re-opened although there were still “residual delays” of about five miles approaching the crash scene.