State Trunk Highway 38 (often called Highway 38, STH 38 or WIS 38) is a state highway in the U.S. state of Wisconsin. It is a north–south route that runs through Racine and Milwaukee Counties from downtown Racine in the south to downtown Milwaukee in the north.

In Racine County, Highway 38 begins near the lake front at the corner of Main Street (also known as WIS 32) and State Street. Highway 38 turns to the northwest at the intersection of State and Memorial Drive, becoming Northwestern Avenue. Just outside of the town of Franksville, WIS 38 turns north until it reaches County Highway G at Six Mile Road. Turning west, it cuts over to Howell Avenue near Husher.

In Milwaukee County, most of Highway 38 is known as South Howell Avenue, and runs parallel to I-94. Just north of Howard Avenue, Highway 38 becomes South Chase Avenue, which winds across I-94 to intersect with South 6th Street. Highway 38 ends at the intersection of 6th and National Avenue (also known as WIS 59). South 6th Street continues north across a viaduct into downtown Milwaukee.

The section of WIS 38 between Oakwood Road in Oak Creek and Northwestern Avenue near Franksville is currently in the developmental phase for complete reconstruction and relocation. the Wisconsin Department of Transportation has listed several alternatives for rerouting the highway. All of the alternatives would occur in Racine County, and would involve the bypassing of the existing stretch between Five Mile Road (CTH G) and Northwestern Avenue (CTH K).