A zipper slider includes a top plate and a bottom plate. A connecting portion is provided between the top plate and the bottom plate. Two guiding slots are formed between the top plate and the bottom plate. One side of the top plate and the bottom plate extends to form first side plates facing each other. The other side of the top plate and the bottom plate extends to form second side plates facing each other. Each first side plate includes a first straight section and a first curved section. Each second side plate includes a second straight section and a second curved section. The first straight section of the first side plate is longer than the second straight section of the second side plate. Via the above arrangement, the insertion pin can be inserted smoothly and a secure locking function is achieved.