Mark E. Neely Jr. (born November 10, 1944, in Amarillo, Texas) is an American historian best known as an authority on the U.S. Civil War in general and Abraham Lincoln in particular.

In 1972 he was named director of the Lincoln Museum in Fort Wayne, Indiana, a position he held for 20 years.

In 1992 Dr. Neely was named the John Francis Bannon Professor of History and American Studies at Saint Louis University.

In 1998 he was named the McCabe Greer Professor of Civil War History at Pennsylvania State University.

[citation needed] According to the review in the Journal of American History, his 2011 book Lincoln and the Triumph of the Nation "is a meticulous study of Civil War-era constitutionalism, a complex and multifaceted book.... Neely has written what is perhaps the most important study of its kind to appear in the last 20 years.