The Metro D Line is a bus rapid transit line in Minneapolis-Saint Paul, Minnesota. The 18.5-mile (29.8 km) route primarily operates on Fremont and Chicago Avenues from Brooklyn Center through Minneapolis to the Mall of America in Bloomington. As part of BRT service, the D Line features "train-like amenities" including improved station facilities, off-board fare payment, modern vehicles, fewer stops, and higher frequency. The current alignment would substantially replace the existing Route 5, the highest ridership bus route in Minnesota.

Metro Transit is the primary public transportation operator in the Minneapolis–Saint Paul area of the U.S. state of Minnesota and the largest operator in the state. Metro Transit has previously been ranked as one of the best public transit systems in the United States. In 2023, the system had a ridership of 44,977,200, or about 145,600 per weekday as of the fourth quarter of 2023.