Provided is a surfactant composition capable of ensuring high fluidity and excellent storage stability while containing a high amount of an internal olefin sulfonate having 16 or more and 18 or less carbon atoms. The present invention relates to a surfactant composition comprising the following components (A), (B), and (C): (A) 60.0% by mass or more and 71.0% by mass or less of an internal olefin sulfonate having 16 or more and 18 or less carbon atoms, (B) 0.5% by mass or more and 7.5% by mass or less of one or more anionic surfactants selected from the group consisting of (B-1) a fatty acid or a salt thereof, and (B-2) a compound, (B-3) a compound, and (B-4) a compound represented by specific formulas, and (C) water, in which the total content of the component (A) and the component (B) is 66.2% by mass or more and 71.2% by mass or less.
