| Date: | 29 March – 3 April |
| Edition: | 4th |
| Surface: | Clay |
| Location: | Marbella, Spain |
| Champs: |  Gianluca Mager |
| Champd: |  Dominic Inglot /  Matt Reid |
| Before Name: | Marbella Tennis Open |
The 2021 Andalucía Challenger was a professional tennis tournament played on clay courts. It was the fourth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Marbella, Spain between 29 March and 3 April 2021.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Spain | Roberto Carballés Baena | 96 | 1 | |
 Slovakia | Norbert Gombos | 98 | 2 | |
| Spain | Jaume Munar | 99 | 3 | |
| Italy | Gianluca Mager | 102 | 4 | |
| Pedro Sousa | 111 | 5 | ||
 Japan | Taro Daniel | 118 | 6 | |
 Bosnia and Herzegovina | Damir Džumhur | 126 | 7 | |
 Russian Federation | Evgeny Donskoy | 128 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw using a protected ranking:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
See main article: 2021 Andalucía Challenger – Singles.
Gianluca Mager def. Jaume Munar 2–6, 6–3, 6–2.See main article: 2021 Andalucía Challenger – Doubles.
Dominic Inglot / Matt Reid def. Romain Arneodo / Hugo Nys 1–6, 6–3, [10–6].
