Provisional entry lists according to May 17th rankings.
Obviously some of the players will choose not to participate (maybe Nadal, Federer, S. Williams...), some others may not be eligible due to not being part of nominated teams for two Davis Cup / Billie Jean King Cup events.
TENNIS M SINGLES
q 1. SRB 1 Novak Djokovic
2. RUS 1 Daniil Medvedev
3. ESP 1 Rafael Nadal
4. AUT 1 Dominic Thiem
5. GRE 1 Stefanos Tsitsipas
6. GER 1 Alexander Zverev
7. RUS 2 Andrey Rublev
8. SUI 1 Roger Federer
9. ITA 1 Matteo Berrettini
10. ARG 1 Diego Schwartzman
11. ESP 2 Roberto Bautista Agut
12. ESP 3 Pablo Carreno Busta
13. BEL 1 David Goffin
14. FRA 1 Gael Monfils
15. CAN 1 Denis Shapovalov
16. CAN 2 Milos Raonic
17. ITA 2 Jannik Sinner
18. POL 1 Hubert Hurkacz
19. CAN 3 Felix Auger-Aliassime
20. BUL 1 Grigor Dimitrov
21. NOR 1 Casper Ruud
22. AUS 1 Alex de Minaur
23. CHI 1 Cristian Garin
24. SUI 2 Stan Wawrinka
25. RUS 3 Aslan Karatsev
26. RUS 4 Karen Khachanov
27. GBR 1 Daniel Evans
28. ITA 3 Lorenzo Sonego
29. ITA 4 Fabio Fognini
30. CRO 1 Borna Coric
31. GEO 1 Nikoloz Basilashvili
32. USA 1 Taylor Fritz
33. FRA 2 Ugo Humbert
34. USA 2 John Isner
35. USA 3 Reilly Opelka
- FRA - DNS Benoit Paire
36. FRA 3 Adrian Mannarino
37. KAZ 1 Alexander Bublik
38. ESP 4 Albert Ramos-Vinolas
39. SRB 2 Dusan Lajovic
40. SRB 3 Filip Krajinovic
41. GER 2 Jan-Lennard Struff
42. AUS 2 John Millman
43. HUN 1 Marton Fucsovics
- ESP 5 Alejandro Davidovich-Fokina
44. CRO 2 Marin Cilic
45. SRB 4 Miomir Kecmanovic
46. JPN 1 Kei Nishikori
47. GBR 2 Cameron Norrie
48. ARG 2 Federico Delbonis
49. RSA 1 Lloyd Harris
50. FRA 4 Richard Gasquet
51. USA 4 Tommy Paul
- SRB 5 Laslo Djere
52. SLO 1 Aljaz Bedene
53. AUS 3 Nick Kyrgios
- FRA 5 Jeremy Chardy
54. ARG 3 Guido Pella
55. GER 3 Dominik Koepfer
56. JPN 2 Yoshihito Nishioka
Q 57. BRA Joao Menezes (Am1)
58. CHI Tomas Barrios (Am2)
59. UZB Denis Istomin (As1)
60. EGY Mohamed Safwat (Af1)
61. ??? Eu1
62. ??? Oc1
63. ??? L1
64. ??? H1
21.05.17
https://www.atptour.com/en/rankings/singles
https://en.wikipedia.org/wiki/Tennis_at_the_2020_Summer_Olympics_%E2%80%93_Qualification#Men's_singles
TENNIS W SINGLES
q 1. AUS 1 Ashleigh Barty
2. JPN 1 Naomi Osaka
3. ROU 1 Simona Halep
4. BLR 1 Alyna Sabalenka
5. USA 1 Sofia Kenin
6. UKR 1 Elina Svitolina
7. CAN 1 Bianca Andreescu
8. USA 1 Serena Williams
9. POL 1 Iga Świątek
10. CZE 1 Karolina Pliskova
11. SUI 1 Belinda Bencic
12. CZE 2 Petra Kvitova
13. ESP 1 Garbine Muguruza
14. USA 2 Jennifer Brady
15. BEL 1 Elise Mertens
16. BLR 2 Viktoria Azarenka
17. NED 1 Kiki Bertens
18. GRE 1 Maria Sakkari
19. CZE 3 Karolina Muchova
20. GBR 1 Johanna Konta
21. CZE 4 Marketa Vondrousova
22. KAZ 1 Elena Rybakina
23. CRO 1 Petra Martic
24. USA 3 Madison Keys
25. TUN 1 Ons Jabeur
26. GER 1 Angelique Kerber
27. USA 4 Alison Riske
- USA 5 Jessica Pegula
28. RUS 1 Veronika Kudermetova
- USA 6 Cori Gauff
29. EST 1 Anett Kontaveit
30. RUS 2 Anastasia Pavlyuchenkova
- UKR DNS? Dayana Yastremska
31. RUS 3 Ekaterina Alexandrova
32. KAZ 2 Yulia Putintseva
33. CRO 2 Donna Vekic
34. RUS 4 Daria Kasatkina
- CZE 5 Barbora Krejcikova
- RUS 5 Svetlana Kuznetsova
- USA 7 Amanda Anisimova
35. LAT 1 Jelena Ostapenko
36. ARG 1 Nadia Podoroska - Q Am2
37. CHN 1 Shuai Zhang
38. ESP 2 Paula Badosa
- USA 8 Shelby Rogers
39. LAT 2 Anastasija Sevastova
40. POL 2 Magda Linette
41. CHN 2 Qiang Wang - Q As1
42. FRA 1 Fiona Ferro
43. ESP 3 Sara Sorribes Tormo
- USA 9 Danielle Collins
- CZE 6 Marie Bouzkova
44. FRA 2 Caroline Garcia
45. SUI 2 Jil Teichmann
46. GER 2 Laura Siegemund
- CZE 7 Barbora Strycova
47. CHN 3 Saisai Zheng
48. ROU 2 Sorana Cirstea
49. FRA 3 Kristina Mladenovic
50. SWE 1 Rebecca Peterson
51. MNE 1 Danka Kovinic
52. ROU 3 Patricia Maria Tig
53. TPE 1 Su-Wei Hsieh
54. FRA 4 Alize Cornet
- USA 10 Sloane Stephens
55. EST 2 Kaia Kanepi
56. BEL 2 Alison van Uytvanck
Q 57. EGY Mayar Sharif (Af1)
58. ??? Am1
59. ??? Am2
60. ??? As1
61. ??? Eu1
62. ??? Oc1
63. ??? L1
64. ??? H1
21.05.17
https://www.wtatennis.com/rankings/singles
https://en.wikipedia.org/wiki/Tennis_at_the_2020_Summer_Olympics_%E2%80%93_Qualification#Women's_singles