A middle flashing assembly for use in a roof window arrangement mounted in an inclined roof structure and including at least two roof windows each comprising a frame and a pane, where a first roof window is located above a second roof window when seen in the direction of inclination of the roof structure, said middle flashing assembly comprising a middle flashing member comprising a first part and a second part, where the first part is configured for extending between a bottom frame member of the first roof window and a top frame member of the second roof window in the mounted state, said first part having an interior side adapted for facing the interior of a building covered by the roof structure, an exterior side adapted for facing an exterior, a first edge adapted for being located at the first roof window in the mounted state, a second edge adapted for being located at the second roof window and defining a length direction of the middle flashing assembly, and two side edges extending between the first and second edges, where an engagement section configured for engagement with a connector element extending from the frame of the first roof window towards the second roof window is provided at one or both side edges, and where the second part is located on the interior side of the first part, extending from the second edge away from the first part, characterized in that the middle flashing assembly further comprises an edge supporting rail and an edge gasket both extending on the interior side of the middle flashing member in parallel with the second edge, said edge gasket being located between the middle flashing member and the edge supporting rail and having a gasket end section extending beyond the middle flashing member in the length direction, said gasket end section being configured for engagement with the connector element. where the first part is configured for extending between a bottom frame member of the first roof window and a top frame member of the second roof window in the mounted state, said first part having an interior side adapted for facing the interior of a building covered by the roof structure, an exterior side adapted for facing an exterior, a first edge adapted for being located at the first roof window in the mounted state, a second edge adapted for being located at the second roof window and defining a length direction of the middle flashing assembly, and two side edges extending between the first and second edges, where an engagement section configured for engagement with a connector element extending from the frame of the first roof window towards the second roof window is provided at one or both side edges, and where the second part is located on the interior side of the first part, extending from the second edge away from the first part, characterized in that the middle flashing assembly further comprises an edge supporting rail and an edge gasket both extending on the interior side of the middle flashing member in parallel with the second edge, said edge gasket being located between the middle flashing member and the edge supporting rail and having a gasket end section extending beyond the middle flashing member in the length direction, said gasket end section being configured for engagement with the connector element.