Thyroid hormones are critical regulators of development and metamorphosis. There is an emerging understanding that thyroid hormones also regulate gene expression in non-chordate animals. This project contains transcriptomic data of Strongylocentrotus purpuratus larvae at three stages (gastrulation, 23-days post-fertilization, and 27-days post-fertilization) after 24h exposure to either a vehicle control, or to the thyroid hormones, T3 or T4 (10^-7 M concentration).