2018 İstanbul Cup should not be confused with 2018 Istanbul Open.
The 2018 İstanbul Cup (also known as the TEB BNP Paribas İstanbul Cup for sponsorship reasons) was a tennis tournament played on outdoor clay courts. It was the 11th edition of the İstanbul Cup, and part of the WTA International tournaments of the 2018 WTA Tour. It took place in Istanbul, Turkey, from 23 through 29 April 2018.
| Event | W | F | SF | QF | Round of 16 | Round of 32 | width=85 | Q | width=85 | Q2 | width=85 | Q1 |
| Women's singles | 280 | 180 | 110 | 60 | 30 | 1 | 18 | 12 | 1 | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Women's doubles | 1 |
| width=130 bgcolor=dfe2e9 | Event | width=80 bgcolor=lime | W | width=85 bgcolor=thistle | F | width=85 bgcolor=ffff00 | SF | width=85 bgcolor=ffebcd | QF | width=85 bgcolor=afeeee | Round of 16 | width=85 bgcolor=afeeee | Round of 32 | width=85 | Q2 | width=85 | Q1 |
| style=background:#ededed | Women's singles | $43,000 | $21,400 | $11,500 | $6,175 | $3,400 | $2,100 | $1,020 | $600 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| style=background:#ededed | Women's doubles | $12,300 | $6,400 | $3,435 | $1,820 | $960 |
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Caroline Wozniacki | 2 | 1 | ||
 Russian Federation | Svetlana Kuznetsova | 28 | 2 | |
 Poland | Agnieszka Radwańska | 29 | 3 | |
 China | Zhang Shuai | 30 | 4 | |
| Russian Federation | Ekaterina Makarova | 32 | 5 | |
 Romania | Sorana Cîrstea | 34 | 6 | |
| Romania | Irina-Camelia Begu | 38 | 7 | |
 Belarus | Aryna Sabalenka | 47 | 8 |
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
Beatriz Haddad Maia → replaced by 
Christina McHale
Kateryna Kozlova → replaced by 
Ajla Tomljanović
Sara Errani
Naomi Osaka → replaced by Polona Hercog| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
| Ukraine | Kateryna Bondarenko |  Serbia | Aleksandra Krunić | 109 | 1 | |
| Bibiane Schoofs |  Czech Republic | Renata Voráčová | 123 | 2 | ||
| Xenia Knoll |  United Kingdom | Anna Smith | 123 | 3 | ||
| Dalila Jakupović | Russian Federation | Irina Khromacheva | 123 | 4 |
The following pairs received wildcards into the doubles main draw:
See main article: 2018 İstanbul Cup – Singles.
Pauline Parmentier def. Polona Hercog, 6–4, 3–6, 6–3[1]See main article: 2018 İstanbul Cup – Doubles.
Liang Chen / Zhang Shuai def. Xenia Knoll / Anna Smith, 6–4, 6–4
