4th Infantry

4th Infantry may refer to:


 * 2/4th Battalion (Australia)
 * 4th Battalion (Australia)
 * 4th Battalion, 3rd Infantry Regiment (United States)
 * 4th Battalion, Royal Australian Regiment
 * 4th Infantry Division (India)
 * 4th Infantry Division (Poland)
 * 4th Infantry Division (United Kingdom)
 * 4th Infantry Division (United States)
 * 4th Infantry Regiment (United States)
 * 4th New Guinea Infantry Battalion
 * 4th Single Infantry Battalion (Estonia)
 * The Loyal Edmonton Regiment (4th Battalion, Princess Patricia's Canadian Light Infantry)