Ons Jabeur was the defending champion, having won the event in 2013, but chose to compete at the $25,000 ITF tournament in Tunis.
Johanna Konta was the defending champion, but chose not to participate.
Sharon Fichman and Maryna Zanevska were the defending champions, but both players chose not to participate.
Shelby Rogers was the defending champion, having won the event in 2013, but chose not to participate.
Serena Williams was the defending champion, but withdrew due to an elbow injury.
Annika Beck was the defending champion, but lost in the first round to Anna-Lena Friedsam.
Kateryna Bondarenko was the defending champion, but chose not to participate.
This was a new event in the ITF Women's Circuit.
This was a new event in the ITF Women's Circuit.
Venus Williams was the defending champion, but lost in the first round to Daria Kasatkina.
Tatjana Maria was the defending champion, but lost in the first round to Catherine Bellis.
Victoria Azarenka defeated Svetlana Kuznetsova in the final, 6–3, 6–2 to win the women's singles tennis title at the 2016 Miami Open. She became the first woman since Kim Clijsters in 2005 to win Indian Wells and Miami back to back, and became only the third woman in history, after Steffi Graf and Clijsters, to complete the 'Sunshine Double' in singles.
Angelique Kerber was the defending champion, but retired in the semifinals against Sloane Stephens.
Simona Halep defeated Madison Keys in the final, 7–6(7–2), 6–3 to win the women's singles tennis title at the 2016 Canadian Open.
Anna Kalinskaya and Tereza Mihalíková were the defending champions, but Kalinskaya chose to participate in Saint-Gaudens instead. Mihalíková partnered Chantal Škamlová, but they lost in the first round to Chuang Chia-jung and Renata Voráčová.
Marina Melnikova was the defending champion, but chose not to participate.
It was the first edition of this women's tennis event.
Tímea Babos was the defending champion, but lost in the second round to Mona Barthel.
Nao Hibino and Alicja Rosolska were the defending champions, but Rosolska chose to compete in Charleston instead. Hibino played alongside Darija Jurak, but lost in the quarterfinals to Valeria Savinykh and Yana Sizikova.
Naomi Broady and Heather Watson were the defending champions, however Watson chose not to participate, while Broady chose to compete at the 2018 Kurume U.S.E Cup.
Michaëlla Krajicek 
Naomi Broady 
