The 2015 Nielsen Pro Tennis Championship was a professional tennis tournament played on hard courts. It was the 24th edition of the tournament which was part of the 2015 ATP Challenger Tour. It took place in Winnetka, Illinois, between 6 and 12 July 2015.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Japan | Tatsuma Ito | 94 | 1 | |
 Ukraine | Illya Marchenko | 106 | 2 | |
| Blaž Kavčič | 114 | 3 | ||
| Austin Krajicek | 121 | 4 | ||
| Ryan Harrison | 124 | 5 | ||
| Japan | Yūichi Sugita | 125 | 6 | |
 India | Somdev Devvarman | 136 | 7 | |
| Connor Smith | 139 | 8 |
The following players received wildcards into the singles main draw:
Tom Fawcett Jared Hiltzik Stefan Kozlov Mackenzie McDonaldThe following player received entry as an alternate into the singles main draw:
The following players received entry from the qualifying draw:
Marcos Giron Nicolas Meister Dennis Nevolo
Andrew WhittingtonThe following player received entry as a lucky loser:
See main article: 2015 Nielsen Pro Tennis Championship – singles.
Somdev Devvarman def. Daniel Nguyen, 7–5, 4–6, 7–6(7–5)See main article: 2015 Nielsen Pro Tennis Championship – doubles.
Johan Brunström / Nicholas Monroe def. Sekou Bangoura / 
Frank Dancevic, 4–6, 6–3, [10–8]