Provided are copolymers which provide improved overall performance in terms of fuel economy and wet grip performance, as well as rubber compositions and tires containing the copolymers. Included is a copolymer obtained by copolymerizing an aromatic vinyl compound, a conjugated diene compound, and a compound represented by the formula (1) below or by copolymerizing a conjugated diene compound and a compound represented by the formula (1) below, the copolymer having a weight average molecular weight of 1.0×103 to 2.5×106, wherein R1 and R2 may be the same or different and each represents a functional group containing at least two selected from the group consisting of carbon, hydrogen, and silicon, and R1 and R2 may be joined together to form a ring structure.