Interstate 155 (abbreviated I-155) is an east–west spur beginning in far southeast Missouri. The western terminus is south of Hayti, Missouri at Interstate 55, exits 17A (Interstate 55 northbound) and exit 17B (Interstate 55 southbound). The route proceeds east to the Tennessee border, where it crosses over the Mississippi River. Interstate 155 continues east towards Dyersburg, Tennessee before terminating at US 51, where US 412 continues its route south towards Jackson, Tennessee.

US 412 overlaps the entire length of I-155.

I-155 was once planned as Interstate 24W, and would have continued from Dyersburg southeast to Jackson, Tennessee; a similar route was built as a four-lane expressway (with interchanges at most of the major intersections) in the 1990s and signed as part of US 412.

The proposed extension of I-69 will intersect I-155 northwest of Dyersburg and replace the remainder of I-155 east of that point, reducing the length of I-155 by approximately 8 miles (13 km).