:1918 U.S. National Championships (tennis)

{{Use mdy dates|date=July 2023}}

{{Use American English|date=July 2023}}

{{TennisEventInfo|1918|U.S. National Championships|

| date = August 26 – September 3 (M)
June 17 – 22 (W)

| edition = 38th

| category = Grand Slam (ITF)

| location = Forest Hills, Queens
New York City, New York (M)
Chestnut Hill, PA, U.S. (W)

| venue=West Side Tennis Club (M)
Philadelphia Cricket Club (W)

| surface = Grass

| champms={{flagicon|USA|1912}} Robert Lindley Murray{{cite book|last=Collins|first=Bud|title=The Bud Collins History of Tennis|year=2010|publisher=New Chapter Press|location=[New York]|isbn=978-0942257700|edition=2nd|pages=454–483}}

| champws={{flagicon|NOR}} Molla Bjurstedt

| champmd= {{nowrap| {{flagicon|USA}} Bill Tilden / {{flagicon|USA}} Vincent RichardsCollins, p. 477}}

| champwd= {{nowrap| {{flagicon|USA|1912}} Marion Zinderstein / {{flagicon|USA}} Eleonora SearsCollins, p. 479}}

| champxd= {{nowrap| {{flagicon|USA|1912}} Hazel Wightman / {{flagicon|USA|1912}} Irving WrightCollins, p. 481}}

}}

The 1918 U.S. National Championships (now known as the US Open) was a tennis tournament that took place on the outdoor grass courts at the West Side Tennis Club, Forest Hills in New York City, New York. The women's tournament was held from June 17 until June 22 while the men's tournament ran from August 26 until September 3. It was the 38th staging of the U.S. National Championships and due to World War I the only Grand Slam tennis event of the year.