Simeon T. Josselyn (January 14, 1842 – April 4, 1905) was a first lieutenant in the Union Army who was awarded the Medal of Honor for his actions during the American Civil War at the Battle of Missionary Ridge.

He was awarded the medal "for extraordinary heroism on 25 November 1863, while serving with Company C, 13th Illinois Infantry, in action at Missionary Ridge, Tennessee.

While commanding his company, deployed as skirmishers, First Lieutenant Josselyn came upon a large body of the enemy, taking a number of them prisoner.

[2] In this action against the 18th Alabama Infantry, Josselyn single-handedly captured the nine men of the regimental color guard, who were returned to the Union lines as prisoners.

Josselyn was a Mason and a member of the Grand Army of the Republic and Military Order of the Loyal Legion of the United States.