The Second Battle of Newtonia was fought on October 28, 1864, near Newtonia, Missouri, between cavalry commanded by Major General James G. Blunt of the Union Army and Brigadier General Joseph O. Shelby's rear guard of the Confederate Army of Missouri. In September 1864, Confederate Major General Sterling Price had entered the state of Missouri with hopes of creating a popular uprising against Union control of the state. A defeat at the Battle of Pilot Knob in late September and the strength of Union positions at Jefferson City led Price to abandon the main objectives of the campaign; instead he moved his force west towards Kansas City, where it was badly defeated at the Battle of Westport by Major General Samuel R. Curtis on October 23. Following a set of three defeats on October 25, Price's army halted to rest near Newtonia on October 28.

James G. Blunt was an American physician and abolitionist who rose to the rank of major general in the Union Army during the American Civil War. He was defeated by Quantrill's Raiders at the Battle of Baxter Springs in Kansas in 1863, but is considered to have served well the next year as a division commander during Price's Raid in Missouri.