A grain-oriented electrical steel sheet, comprising: a steel sheet having a steel sheet surface in which a groove, which extends in a direction intersecting a rolling direction and of which a groove depth direction matches a sheet thickness direction, is formed, wherein in a case where the groove is seen on a longitudinal groove cross-section including a groove extension direction and the sheet thickness direction, an arithmetic average height Ra of a roughness curve, which constitutes a contour of a groove bottom region of the groove, is 1 μm to 3 μm, and an average length RSm of a roughness curve element, which constitutes the contour of the groove bottom region, is 10 μm to 150 μm, the grain-oriented electrical steel sheet further includes an insulating film, in a case where the groove is seen on a transverse groove cross-section that is perpendicular to the groove extension direction, when a region, which is spaced away from a base point, that is a boundary between the groove and the steel sheet surface, by 10 μm to 500 μm in a direction that is perpendicular to the sheet thickness direction and points away from the groove on the transverse groove cross-section, is defined as a particle existing region, the insulating film in the particle existing region includes iron-containing particles having an equivalent circle diameter of 0.1 μm to 2 μm, a ratio of an area of the iron-containing particles to an area of the particle existing region is equal to or greater than 0.1% and less than 30%, and a chemical composition of the iron-containing particles contains 80 to 100 mass% of Fe, and 0 to 10 mass% of Si, and 0 to 10 mass% of Mg. a steel sheet having a steel sheet surface in which a groove, which extends in a direction intersecting a rolling direction and of which a groove depth direction matches a sheet thickness direction, is formed, wherein in a case where the groove is seen on a longitudinal groove cross-section including a groove extension direction and the sheet thickness direction, an arithmetic average height Ra of a roughness curve, which constitutes a contour of a groove bottom region of the groove, is 1 μm to 3 μm, and an average length RSm of a roughness curve element, which constitutes the contour of the groove bottom region, is 10 μm to 150 μm, the grain-oriented electrical steel sheet further includes an insulating film, in a case where the groove is seen on a transverse groove cross-section that is perpendicular to the groove extension direction, when a region, which is spaced away from a base point, that is a boundary between the groove and the steel sheet surface, by 10 μm to 500 μm in a direction that is perpendicular to the sheet thickness direction and points away from the groove on the transverse groove cross-section, is defined as a particle existing region, the insulating film in the particle existing region includes iron-containing particles having an equivalent circle diameter of 0.1 μm to 2 μm, a ratio of an area of the iron-containing particles to an area of the particle existing region is equal to or greater than 0.1% and less than 30%, and a chemical composition of the iron-containing particles contains 80 to 100 mass% of Fe, and 0 to 10 mass% of Si, and 0 to 10 mass% of Mg.