A prepolymer is prepared by subjecting a compound of Formula (I) and a vinyl-containing compound to a prepolymerization reaction, and a resin composition includes the prepolymer. The vinyl-containing compound includes bis(vinylphenyl) ethane, divinylbenzene, modification of divinylbenzene or a combination thereof. A ratio in part by weight of the compound of Formula (I) to the vinyl-containing compound in the prepolymerization reaction is 8:2 to 6:4. The resin composition includes the prepolymer and an additive, and an article made from the resin composition may include a resin film, a prepreg, a laminate or a printed circuit board.