A74(M) J18 is a junction on the A74(M) motorway, connecting it to the B723 in a half-diamond arrangement, providing a northbound exit from the A74(M) to the B723, and a southbound entry. The current junction opened in September 1994 when the motorway replaced the old A74 dual carriageway past Lockerbie.
Before the motorway was built, a similar junction existed to the north of the current junction, providing the same movements as the current junction does. The old junction opened in 1965 with the A74 Lockerbie bypass, and was demolished when the motorway was built. A roundabout connecting the B7076 and B723 now exists on the site of the old junction. The old A74 (now B7076 and single carriageway) passes to the east of the current junction, and the B723 has been re-routed to pass through the current junction before meeting the B7076 at a T-junction and going onto the line of the old A74 before reaching the roundabout at the site of the old junction. (Approaching from the south, it would have previously headed northwards in a straight line and crossed the line of the motorway a little to the north of the current junction, before crossing over the A74 at the site of the old junction and into Lockerbie.)