Arrott Transportation Center is an elevated rapid transit station and bus station serving SEPTA's Market–Frankford Line and City Bus routes. It is located at the intersection of Frankford Avenue, Oxford Avenue, Arrott Street, Paul Street, and Margaret Street in the Frankford neighborhood of Northeast Philadelphia, Pennsylvania. The terminal was originally known by two separate names, Margaret–Orthodox station for the Market–Frankford Line and Arrott Bus Terminal for bus routes.

The Market–Frankford Line (MFL), or the Blue Line) is one of three rapid transit lines in Philadelphia, Pennsylvania; it and the Broad Street Line are operated by SEPTA, and the PATCO Speedline is operated by PATCO. The Market–Frankford Line runs from the 69th Street Transportation Center in Upper Darby, just outside of West Philadelphia, through Center City Philadelphia to the Frankford Transportation Center in Near Northeast Philadelphia. From 2024 onwards, this line will be rebranded as the L line.