A tape cassette used for a printer includes a thermal head and a cassette holder to which the tape cassette is attachable. The tape cassette includes a tape roll, a casing, a regulation guide and a pressure member. The tape roll is formed by winding a tape. The tape has a width defining a widthwise direction. The casing accommodates therein the tape roll. A tape conveying passage is defined in the casing. The regulation guide is positioned at the tape conveying passage to restrict displacement of the tape in the widthwise direction. The pressure member is positioned upstream of the regulation guide in a conveying direction of the tape and along the tape conveying passage. The pressure member is in contact with the tape in a contacting direction to apply pressing force to the tape in the contacting direction.