:1978 US Open (tennis)

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

{{TennisEventInfo|1978|US Open|

| date = August 28 – September 10

| edition = 98th

| surface = Hardcourt

| category = Grand Slam (ITF)

| location = Flushing Meadows, New York City, United States

| venue = National Tennis Center

| attendance = 275,300

| champms={{flagicon|USA}} Jimmy Connors{{cite web|title=ATP – 1978 US Open Men's Singles Draw|url=http://www.atpworldtour.com/Share/Event-Draws.aspx?Year=1978&EventId=560&Draw=ms|publisher=ATP}}

| champws={{flagicon|USA}} Chris Evert{{cite web|title=WTA – 1978 Tournaments – US Open|url=https://wtafiles.blob.core.windows.net/pdf/draws/archive/1978/905.pdf |publisher=WTA |format=PDF}}

| champmd={{flagicon|USA}} Bob Lutz / {{flagicon|USA}} Stan Smith{{cite web|title=ATP – 1978 US Open Men's Doubles Draw|url=http://www.atpworldtour.com/Share/Event-Draws.aspx?Year=1978&EventId=560&Draw=md|publisher=ATP}}

| champwd={{flagicon|USA}} Billie Jean King / {{flagicon|USA}} Martina Navratilova

| champxd={{flagicon|NED}} Betty Stöve / {{flagicon|RSA|1928}} Frew McMillan

}}

The 1978 US Open was a tennis tournament played on outdoor hard courts at the USTA National Tennis Center in New York City in New York in the United States. It was the 98th edition of the US Open and the third Grand Slam tennis event of the year. The tournament was held from August 28 to September 10, 1978, and the singles titles were won by Jimmy Connors and Chris Evert.{{cite web |author1=Harvey Araton |title=The stories that would have been: the 1978 U.S. Open |url=https://www.nytimes.com/2018/08/23/sports/tennis/1978-us-open-evert-connors.html |website=The New York Times |date=August 23, 2018}} This was the first year the US Open was played at the National Tennis Center in Flushing Meadows after having been organized at the West Side Tennis Club venue in Forest Hills since 1915. It was also the first time the tournament was played on hard courts, as opposed to much of its history on grass and a brief stint, from 1975 through 1977, on clay.{{cite web|title=The Greatest Achievements in US Open History|url=http://www.usta.com/About-USTA/Organization/USTA-Magazine/The_Greatest_Achievements_in_US_Open_history/|publisher=USTA|author=Mark Preston|author2=E.J. Crawford & Joel Drucker}}