A foldable safety barrier to be secured in and removed from a door opening, comprising a frame having a covering member (28), such as a piece of fabric, said frame being formed by upper and lower cross members (1, 2) connected with first and second lateral posts (3, 4) by means of four angle brackets (5, 6, 7, 8), each of which has first and second legs, and constructed such that the upper (1) and lower (2) cross members consist of two pipes (9, 10) which are mutually displaceable, while the first and second lateral posts (3, 4) consist of two pipes (13, 14) which are interconnected by means of lockable hinge links (15, 19). The outer dimensions of the hinge links (15, 19) correspond to the outer dimensions of the lateral posts (3, 4). Two of the four angle brackets (5, 6, 7, 8) have arranged therein a threaded rod (29) having a ferrule (30) and optional pressure indicators, while a spring-biased threaded rod (24) having a ferrule (25) is arranged in the third angle bracket, and a housing (21) having a block movable in the housing (21) is arranged in the fourth angle bracket. The invention provides a foldable safety barrier having incorporated safety means, it being ensured that children cannot climb over the barrier as there are no faces on which the child can support its foot. Further, it can always be checked whether the barrier is fixed in a frame with a sufficient force.