The invention is concerned with a panel assembly including at least two panels and a connector member for mounting the panels to a support surface, the panels being positioned edge-to-edge in coplanar relationship with the respective confronting edges thereof spaced apart, and the connector member between the confronting panel edges and interlocking the panels together by being fixedly secured to the support surface. Each panel has first and second surfaces lying respectively in first and second parallel planes and has on its respective confronting edge a tongue and a groove, the tongue and groove extending along the panel edge and between the first and second planes, and respectively projecting and opening outwardly angularly towards the first plane. The connector member comprises an elongated body filling the space between the confronting panel edges and having on each side thereof a tongue and a groove respectively projecting and opening outwardly angularly towards the second plane; the tongue and groove on either side are complementary to and lockingly engage with the respective groove and tongue on the adjacent respective confronting edges of the panels. The connector member cooperates with the panels to urge the panels towards one another in tight locking engagement as a result of a compressive force being exerted on the member in a direction towards the support surface when the member is secured to the support surface. The provision of such connector member does away with the hitherto practice of driving nails or screws in the panel edges to fix the panels to the support surface, while still providing a tight locking engagement between the panels.