The 2021 Singapore Tennis Open is a tournament on the 2021 ATP Tour. It is played on indoor hard courts in Singapore. It is organised with a single-year licence in 2021, and was held at OCBC Arena in Singapore from February 22 to February 28, 2021.
<sub>*per team</sub>
The following players received wildcards into the main draw:
The following player received an entry using a protected ranking into the main draw:
The following players received entry from the qualifying draw:
The following pairs received wildcards into the doubles main draw: