An anti-climbing barrier 1 comprises a planar support element 2, a bulbous barrier element 7 with a curved section 12 and a bracing element 41. The support and barrier elements are connected at their top edges 6, 8, forming a space for receiving the upper part of a wall 4. The bracing element protrudes from the barrier element to help secure the barrier to the top of the wall. The support and barrier elements may be permanently connected to one another, and may be formed from a single sheet of material. The barrier may comprise two or more bracing elements, and may comprise a second support element. The bracing element may form a downward facing channel. A method of installing a barrier may include the use of connectors driven into the wall, whilst a plurality of barriers may be placed adjacent to one another on top of the wall.
