Justus Smith Stearns (April 10, 1845 – February 14, 1933) was an American lumber baron and businessman. He was involved in many enterprises that involved commercial real estate development, sawmills, coal, farming, railroading, and electrical technology. He started his lumber pursuits as a teenager at his father's sawmills. From the business knowledge he learned from his father he became a lumber merchant in his twenties.