The present invention provides an innerliner rubber composition having an excellent balance of sheet processability and air retention properties, and a pneumatic tire including the rubber composition. The present invention relates to an innerliner rubber composition, containing a rubber component; a mixture of a fatty acid metal salt and a fatty acid amide; an oil; and a C5 petroleum resin, the rubber component including, based on 100% by mass thereof, at least 70% by mass of a butyl-based rubber, the mixture being present in an amount of 0.8 to 3.2 parts by mass per 100 parts by mass of the rubber component, the mixture, the oil, and the C5 petroleum resin being present in a combined amount of 6.0 to 16.0 parts by mass per 100 parts by mass of the rubber component.