A tyre comprising: a tread portion having a designated mounting direction to a vehicle, the tread portion comprising a first tread edge and a second tread edge to be located outwardly and inwardly of a vehicle, respectively, when being mounted to the vehicle, two or more main grooves extending continuously in a tyre circumferential direction between the first tread edge and the second tread edge, and two or more land portions divided by the main grooves, wherein the main grooves comprise a first shoulder main groove disposed between the first tread edge and a tyre equator, a second shoulder main groove disposed between the second tread edge and the tyre equator, and a crown main groove disposed between the first shoulder main groove and the second shoulder main groove, the land portions comprise a first middle land portion defined between the first shoulder main groove and the crown main groove, and a second middle land portion defined between the second shoulder main groove and the crown main groove, the first middle land portion is provided with two or more first middle lateral grooves traversing the first middle land portion completely in a tyre axial direction, and the second middle land portion is provided with two or more second middle lateral grooves traversing the second middle land portion completely in the tyre axial direction, characterized in that in a plan view of the tread portion, each of the first middle lateral grooves and the second middle lateral grooves is a curved groove which comprises a first convex portion (16a, 17a) located on a first side with respect to a groove-reference-straight-line (16c, 17c) that connects both ends of a groove centerline of the curved groove (16, 17) and a second convex portion (16b, 17b) located on a second side with respect to the groove-reference-straight-line (16c, 17c), and a length in the tyre circumferential direction of the groove-reference-straight-line of each first middle lateral groove is smaller than a length in the tyre circumferential direction of the groove-reference-straight-line of each second middle lateral groove. a tread portion having a designated mounting direction to a vehicle, the tread portion comprising a first tread edge and a second tread edge to be located outwardly and inwardly of a vehicle, respectively, when being mounted to the vehicle, two or more main grooves extending continuously in a tyre circumferential direction between the first tread edge and the second tread edge, and two or more land portions divided by the main grooves, the main grooves comprise a first shoulder main groove disposed between the first tread edge and a tyre equator, a second shoulder main groove disposed between the second tread edge and the tyre equator, and a crown main groove disposed between the first shoulder main groove and the second shoulder main groove, the land portions comprise a first middle land portion defined between the first shoulder main groove and the crown main groove, and a second middle land portion defined between the second shoulder main groove and the crown main groove, the first middle land portion is provided with two or more first middle lateral grooves traversing the first middle land portion completely in a tyre axial direction, and the second middle land portion is provided with two or more second middle lateral grooves traversing the second middle land portion completely in the tyre axial direction, characterized in that in a plan view of the tread portion, each of the first middle lateral grooves and the second middle lateral grooves is a curved groove which comprises a first convex portion (16a, 17a) located on a first side with respect to a groove-reference-straight-line (16c, 17c) that connects both ends of a groove centerline of the curved groove (16, 17) and a second convex portion (16b, 17b) located on a second side with respect to the groove-reference-straight-line (16c, 17c), and a length in the tyre circumferential direction of the groove-reference-straight-line of each first middle lateral groove is smaller than a length in the tyre circumferential direction of the groove-reference-straight-line of each second middle lateral groove.