| Date: | 9–15 August 2021 |
| Edition: | 14th |
| Surface: | Hard |
| Location: | Landisville, Pennsylvania, United States |
| Category: | ITF Women's World Tennis Tour |
| Draw: | 32S / 16D |
| Prize Money: | $100,000 |
| Champs: |  Nuria Párrizas Díaz |
| Champd: |  Hanna Chang / Alexa Glatch |
| Before Year: | 2019 |
The 2021 Koser Jewelers Tennis Challenge was a professional women's tennis tournament played on outdoor hard courts. It was the fourteenth edition of the tournament which was part of the 2021 ITF Women's World Tennis Tour. It took place in Landisville, Pennsylvania, United States between 9 and 15 August 2021.[1]
| Event | W | F | SF | QF | Round of 16 | Round of 32 | width=85 | Q | width=85 | Q2 | width=85 | Q1 |
| Women's singles | 140 | 85 | 50 | 25 | 13 | 1 | 6 | 4 | 0 | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 | $15,239 | $8,147 | $4,473 | $2,573 | $1,559 | $926 | $509 | $316 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| style=background:#ededed | Women's doubles | $5,573 | $2,787 | $1,393 | $760 | $507 |
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Madison Brengle | 78 | 1 | ||
| Clara Tauson | 97 | 2 | ||
| Spain | Nuria Párrizas Díaz | 109 | 3 | |
 Belgium | Greet Minnen | 111 | 4 | |
| Belgium | Ysaline Bonaventure | 127 | 6 | |
 Russian Federation | Anna Kalinskaya | 133 | 7 | |
| Caty McNally | 134 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry using a protected ranking:
The following players received entry from the qualifying draw:
Ekaterine Gorgodze
Beatriz Haddad Maia
Mayo Hibi Mai Hontama
Emma Raducanu
Ankita Raina
Daria SnigurThe following player received entry as a Lucky loser:
See main article: 2021 Koser Jewelers Tennis Challenge – Singles.
Nuria Párrizas Díaz def. Greet Minnen, 7–6(8–6), 4–6, 7–6(9–7)See main article: 2021 Koser Jewelers Tennis Challenge – Doubles.
Hanna Chang / Alexa Glatch def. Samantha Murray Sharan / Valeria Savinykh, 7–6(7–3), 3–6, [11–9]