The 2013 U.S. Men's Clay Court Championships was a men's tennis tournament played on outdoor clay courts. It was part of the 2013 ATP World Tour. It was the 45th edition of the U.S. Men's Clay Court Championships, and an ATP World Tour 250 event. It took place at River Oaks Country Club in Houston, Texas, United States, from April 8 through April 14, 2013. Fifth-seeded John Isner won the singles title.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Spain | Nicolás Almagro | 12 | 1 | |
| Tommy Haas | 14 | 2 | ||
 Argentina | Juan Mónaco | 19 | 3 | |
 United States | Sam Querrey | 20 | 4 | |
| United States | John Isner | 23 | 5 | |
| Spain | Fernando Verdasco | 30 | 6 | |
 Italy | Paolo Lorenzi | 57 | 7 | |
| United States | Michael Russell | 73 | 8 |
The following players received wildcards into the main draw:
The following players received entry via the qualifying draw:
The following player received entry as a lucky loser:
| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
| United States | Bob Bryan | United States | Mike Bryan | 2 | 1 | |
 Mexico | Santiago González | United States | Scott Lipsky | 61 | 2 | |
| Treat Conrad Huey |  United Kingdom | Dominic Inglot | 65 | 3 | ||
| United States | Eric Butorac |  Israel | Jonathan Erlich | 99 | 4 |
The following pairs received wildcards into the doubles main draw:
See main article: 2013 U.S. Men's Clay Court Championships – Singles.
John Isner defeated Nicolás Almagro, 6–3, 7–5See main article: 2013 U.S. Men's Clay Court Championships – Doubles.
Jamie Murray / 
John Peers defeated Bob Bryan / Mike Bryan, 1–6, 7–6(7–3), [12–10]