The accident happened on the A74(M) northbound, between junctions 14 and 15 in Moffat, at about 10.15.
Three men were injured. There were not thought to have been any passengers on board the coaches.
Two men were taken to Wishaw General Hospital and the third to Dumfries and Galloway Royal Infirmary.
Their conditions are not known.
Diversions were set up following the closure.
One lane remained closed on Saturday evening while recovery work was carried out after debris was left scattered on the carriageway.
The northbound section of the main road into Scotland has been reopened following a crash involving two coaches and a lorry.