A rubber composition for a tire superior in low heat build-up (tan δ) and superior in fracture strength is provided. A rubber composition for a tire comprising (B) 5 to 80 parts by mass of silica based on 100 parts by mass of (A) including (a) 10 to 60% by mass of a butadiene rubber including 2.5 to 20% by mass of 1,2-syndiotactic polybutadiene crystals, (b) 5 to 60% by mass of a modified diene rubber and (c) 20 to 75% by mass of a diene rubber other than (a) and (b).