The long, thin, ribbon-like pasta traditionally associated with Bolognese sauce is tagliatelle.
Tagliatelle is an egg pasta from the Emilia-Romagna region of northern Italy. Its name comes from the Italian tagliare, meaning “to cut,” because the dough is rolled into sheets and cut into long ribbons. The strands are wider than spaghetti and typically narrower than broad lasagne sheets.
Tagliatelle is famously served with ragù alla bolognese, the meat-based sauce associated with Bologna. The wider, flat shape provides plenty of surface area for the rich sauce to cling to. In traditional Italian usage, Bolognese ragù is paired with fresh tagliatelle rather than spaghetti, despite the popularity of “spaghetti Bolognese” outside Italy.
Fettuccine is a close visual relative and can sometimes be used similarly, but it is more strongly associated with central Italian cooking, especially Roman and Lazio traditions. Linguine has a flattened shape but is narrower, while spaghetti is round rather than ribbon-like. Tagliatelle’s regional identity and classic pairing make it the canonical answer here.