The 2018 U.S. Women's Open was the 73rd U.S. Women's Open, played May 31 – June 3 at Shoal Creek Club in Shoal Creek, Alabama, a suburb southeast of Birmingham.
 The U.S. Women's Open is the oldest of the five current major championships and the second of the 2018 season. It has the largest purse in women's golf at $5 million. The tournament was televised by Fox Sports 1 and Fox Sports.
 The championship was moved up in the schedule this year; it had been played in July for decades, with a few exceptions. Also, the playoff format was modified as part of USGA changes for the four U.S. Open championships in golf (Open, Women's Open, Senior Open, Senior Women's) in 2018, reduced from three to two aggregate holes, followed by sudden death.
 Ariya Jutanugarn won the championship in a playoff over Kim Hyo-joo, which ended on the fourth extra hole.
 The championship was open to any female professional or amateur golfer with a USGA handicap index not exceeding 2.4. Players qualified by competing in one of 24 36-hole qualifying tournaments held at sites across the United States and at international sites in China, England, Japan, and South Korea. Additional players were exempt from qualifying because of past performances in professional or amateur tournaments around the world.
 Many players were exempt in multiple categories. Players are listed only once, in the first category in which they became exempt, with additional categories in parentheses () next to their names. Golfers qualifying in Category 12 who qualified in other categories are denoted with the tour by which they qualified.
 1. Winners of the U.S. Women's Open for the last ten years (2008–2017)
 Chun In-gee (7,9,14,15), Paula Creamer, Ji Eun-hee (9,10,11,14,15), Brittany Lang (9), Inbee Park (4,5,9,10,11,14,15), Park Sung-hyun (8,9,11,14,15), Ryu So-yeon (6,8,9,14,15), Michelle Wie (9,10,11,14,15)
 2. Winner and runner-up from the 2017 U.S. Women's Amateur; winner of the 2017 U.S. Girls' Junior and U.S. Women's Mid-Amateur (must be an amateur)
 Kelsey Chugg (a), Sophia Schubert (a), Erica Shepherd (a), Albane Valenzuela (a)
 3. Winner of the 2017 Mark H. McCormack Medal (Women's World Amateur Golf Ranking) (must be an amateur)
 4. Winners of the Women's PGA Championship for the last five years (2013–2017)
 Brooke Henderson (9,10,11,14,15), Danielle Kang (9,14,15)
 5. Winners of the Ricoh Women's British Open for the last five years (2013–2017)
 Ariya Jutanugarn (9,10,11,14,15), In-Kyung Kim (9,11,14,15), Stacy Lewis (9,11,14,15), Mo Martin (9)
 6. Winners of the ANA Inspiration for the last five years (2014–2018)
 Lydia Ko (7,9,11,14,15), Brittany Lincicome (9,11,14,15), Pernilla Lindberg (9,10,11,14,15), Lexi Thompson (9,11,14,15)
 7. Winners of the Evian Championship for the last five years (2013–2017)
 Kim Hyo-joo (9), Anna Nordqvist (9,11,14,15)
 8. Ten lowest scorers and anyone tying for 10th place from the 2017 U.S. Women's Open
 Choi Hye-jin (14,15), Carlota Ciganda (9,12-LET,14,15), Shanshan Feng (9,10,11,14,15), M. J. Hur (9,14,15), Kim Sei-young (9,14,15), Lee Jeong-eun (12-KLPGA,14,15), Mirim Lee (9,14,15), Amy Yang (9,14,15)
 9. Top 75 money leaders from the 2017 final official LPGA money list
 Marina Alex (14,15), Brittany Altomare (14,15), Nicole Broch Larsen, Ashleigh Buhai, Peiyun Chien, Chella Choi (14), Cydney Clanton, Jacqui Concolino, Austin Ernst, Jodi Ewart Shadoff (14,15), Sandra Gal, Hsu Wei-ling, Charley Hull (14,15), Karine Icher, Moriya Jutanugarn (10,11,14,15), Kim Kaufman, Cristie Kerr (11,14,15), Megan Khang, Katherine Kirk, Jessica Korda (10,11,14,15), Nelly Korda (14,15), Olafia Kristinsdottir, Candie Kung, Lee Jeong-eun, Lee Mi-hyang (11,14,15), Minjee Lee (11,14,15), Gaby López, Caroline Masson (15), Ally McDonald, Azahara Muñoz (12-LET,14), Haru Nomura, Su-Hyun Oh, Ryann O'Toole, Jane Park, Pornanong Phatlum, Madelene Sagström, Lizette Salas (14,15), Alena Sharp, Jenny Shin (14,15), Sarah Jane Smith, Jennifer Song (14,15), Angela Stanford, Ayako Uehara, Jing Yan, Angel Yin (15), Yoo Sun-young
 10. Top 10 money leaders from the 2018 official LPGA money list, through the close of entries on April 25
 Ko Jin-young (11,12-KLPGA,14,15)
 11. Winners of LPGA co-sponsored events, whose victories are considered official, from the conclusion of the 2017 U.S. Women's Open to the initiation of the 2018 U.S. Women's Open
 12. Top five money leaders from the 2017 Japan LPGA Tour, Korea LPGA Tour and Ladies European Tour
 Georgia Hall (14,15), Kim Ji-hyun, Lee Min-young (14,15), Teresa Lu (14,15), Klára Spilková, Ai Suzuki (14,15), Anne van Dam
 13. Top three money leaders from the 2017 China LPGA Tour
 Saranporn Langkulgasettrin, Lee Solar, Supamas Sangchan
 14. Top 50 point leaders from the current Rolex Rankings and anyone tying for 50th place as of April 25
 Nasa Hataoka (15)
 15. Top 50 point leaders from the current Rolex Rankings and anyone tying for 50th place as of May 28
 16. Special exemptions selected by the USGA
 Karrie Webb
 Additional players qualified through sectional qualifying tournaments which took place May 2–17 at sites in the United States, China, South Korea, England, and Japan.
 May 2 at Canoe Brook Country Club, Summit, New Jersey 
 May 2 at Indiana Country Club, Indiana, Pennsylvania
 May 3 at Industry Hills Golf Club, City of Industry, California
 May 4 at Sugar Mill Country Club, New Smyrna Beach, Florida
 May 6 at Ka'anapali Golf Club, Lahaina, Hawaii
 May 7 at Dunwoody Country Club, Dunwoody, Georgia
 May 7 at Elgin Country Club, Elgin, Illinois
 May 8 at La Purisima Golf Club, Lompoc, California
 May 8 at Ohtone Country Club, Ibaraki Prefecture, Japan
 May 14 at Arizona Country Club, Phoenix, Arizona
 May 14 at Contra Costa Country Club, Pleasant Hill, California
 May 14 at The Ranch Country Club, Westminster, Colorado
 May 14 at Buckinghamshire Golf Club, Buckinghamshire, England
 May 14 at TPC Prestancia, Sarasota, Florida
 May 14 at Dream Park Country Club, Incheon, South Korea
 May 14 at Stillwater Country Club, Stillwater, Minnesota
 May 14 at Las Colinas Country Club, Irving, Texas
 May 14 at Deerwood Golf Club, Kingwood, Texas
 May 14 at Hermitage Country Club, Manakin-Sabot, Virginia
 May 14 at Rainier Golf & Country Club, Seattle, Washington
 May 15 at Bermuda Run Country Club, Advance, North Carolina
 May 16 at Shanghai Qizhong Garden Golf Club, Shanghai, China
 May 16 at Cape Cod National Golf Club, Brewster, Massachusetts
 May 17 at Seagate Country Club, Delray Beach, Florida
 The following players were added to the field before the start of the tournament when spots reserved for exemptions in various categories were not used and to replace players who withdrew from the tournament.
 Jennifer Chang (a), Hailee Cooper (a), Lindy Duncan, Andrea Lee (a), Lee Lopez, Wichanee Meechai, Olivia Mehaffey (a), Emilia Migliaccio (a), Song Gaeun (a), Luna Sobrón Galmés, Sophie Walker, Rumi Yoshiba
 2018 yardages by round
 Source:
 Thursday, May 31, 2018
 Friday, June 1, 2018
Saturday June 2, 2018
 Weather delayed the conclusion of the second round until Saturday.
 Saturday, June 2, 2018
 Sunday, June 3, 2018
 Final round
 Cumulative tournament scores, relative to par
 Source:
 In the first year of the new USGA two-hole aggregate playoff format, the playoff was held on holes 14 and 18, both par fours. Jutanugarn parred both while Kim went birdie-bogey to stay tied and it moved to sudden-death, using the same holes only. Both parred the 14th hole, but Kim again made bogey at the 18th hole while Jutanugarn made another par and won the championship.