The invention relates to a device 10 for stabilising ladders 60 that bridge a floor 70 and an elevated structure, such as an elevated floor 70 in a multi-storey construction. The device 70 includes a body that is fixable to the elevated structure and an arm 50 extending from the body. The arm 50 has a tab 52 which engages a beam 64 of the ladder 60 when the ladder 60 is abutting an edge 40 of the body. In this arrangement, outward sliding movement of a heel of the ladder is prevented and thus the ladder 60 is stabilised.