A tape cassette includes a cassette case having a pair of side faces, a tape roll contained within the cassette case, a discharge guide portion positioned in the cassette case in a first corner portion provided farthest downstream on a feed path for a tape, a tape exposing portion located on the feed path, in the vicinity of the discharge guide portion and on an upstream side in relation to the discharge guide portion, a tape feed roller provided on the upstream side on the feed path from the discharge guide portion and adjacent to a rear side of the tape exposing portion, a first recessed portion formed in the vicinity of the discharge guide portion in one of the side faces included in the first corner portion, and a second recessed portion disposed in a diagonally opposite position in the cassette case from the first corner portion.