A mounting bracket for installation of a window in a roof structure, the mounting bracket comprising a first leg portion and a second leg portion essentially perpendicular to the first leg portion for fastening to the roof structure, where the first leg portion comprises two leg sections (11a, 11b), at least one of the leg sections (11a, 11b) being adapted for connection with a frame member (2, 3, 4, 5) of said window at a corner joint, the two leg sections (11a, 11b) being substantially perpendicular to each other for abutment with adjacent frame members of said window at a corner joint, wherein the first of said two leg sections (11a, 11b) of the first leg portion is adapted to be fastened to a frame member (2, 3, 4, 5) at a corner joint by being provided with a hole for passing through a fastening means such as a screw, and the second of said two leg sections (11a, 11b) of the first leg portion is adapted for abutment at a corner joint with a frame member (2, 3, 4, 5) adjacent to the one to which the first leg section is fastened, and the first of said two leg sections (11a, 11b) of the first leg portion comprises a flange which is essentially perpendicular to the first leg section for engaging a groove (7, 8a, 8b) in a frame member (2, 3, 4, 5) of said window at a corner joint, characterized in that the second leg section is extending essentially perpendicular to said first leg section at the end of a protruding section of said first leg section for abutment of said second leg section at a corner joint of said roof window with a frame member of the roof window adjacent to which the first leg section is abutting, and in that said mounting bracket comprises a third leg portion being in direct connection with said second leg portion, said third leg portion extending in a direction substantially perpendicular to said second leg portion and being displaced in parallel to one of said leg sections (11a, 11b) of said first leg portion, the third leg portion comprising two leg sections (13a, 13b) extending in extension of each other and essentially perpendicular to each other, such that one leg section is provided displaced in parallel with the first leg section of the first leg portion for abutment against a vertical surface of an element of the roof structure, such that a gap is formed between the roof structure and the frame of the window, while the other leg section is extending essentially perpendicular to both the first and the second leg portions (11, 12), and in that the second leg portion and the flange are extending in different planes that are parallel to each other and perpendicular to the first leg section in mutually opposite directions, in order for said second leg portion to be fastenable to the roof structure and at the same time allow said flange to be brought into engagement with a groove of said window frame. wherein the first of said two leg sections (11a, 11b) of the first leg portion is adapted to be fastened to a frame member (2, 3, 4, 5) at a corner joint by being provided with a hole for passing through a fastening means such as a screw, and the second of said two leg sections (11a, 11b) of the first leg portion is adapted for abutment at a corner joint with a frame member (2, 3, 4, 5) adjacent to the one to which the first leg section is fastened, and the first of said two leg sections (11a, 11b) of the first leg portion comprises a flange which is essentially perpendicular to the first leg section for engaging a groove (7, 8a, 8b) in a frame member (2, 3, 4, 5) of said window at a corner joint, characterized in that the second leg section is extending essentially perpendicular to said first leg section at the end of a protruding section of said first leg section for abutment of said second leg section at a corner joint of said roof window with a frame member of the roof window adjacent to which the first leg section is abutting, and in that said mounting bracket comprises a third leg portion being in direct connection with said second leg portion, said third leg portion extending in a direction substantially perpendicular to said second leg portion and being displaced in parallel to one of said leg sections (11a, 11b) of said first leg portion, the third leg portion comprising two leg sections (13a, 13b) extending in extension of each other and essentially perpendicular to each other, such that one leg section is provided displaced in parallel with the first leg section of the first leg portion for abutment against a vertical surface of an element of the roof structure, such that a gap is formed between the roof structure and the frame of the window, while the other leg section is extending essentially perpendicular to both the first and the second leg portions (11, 12), and in that the second leg portion and the flange are extending in different planes that are parallel to each other and perpendicular to the first leg section in mutually opposite directions, in order for said second leg portion to be fastenable to the roof structure and at the same time allow said flange to be brought into engagement with a groove of said window frame.