J. C. Williamson's was an Australian theatrical management company and theatre owner. Colloquially known as The Firm or JCW, the company dominated Australian commercial theatre in the twentieth century and at one time was described as the largest theatrical firm in the world. With its beginnings in the theatrical productions of J. C. Williamson and partners in the nineteenth and early twentieth century, the company J. C. Williamson Limited was established in 1910. It closed under financial pressure in 1976.