Bellucci started 2012 reaching three second rounds in a row, with the Australian Open included, where he lost to Gaël Monfils.

In the Brasil Open, he reached the semifinals losing to Filippo Volandri.
He then went to Indian Wells, where he managed to beat seed 20 Jürgen Melzer and walked over Russian Nikolay Davydenko to equalize his second best ever Masters 1000 campaign, reaching the fourth and losing to Roger Federer in three sets.
At the Monte-Carlo Masters he defeated fifth seeded player David Ferrer to reach third round, where he lost to Robin Haase.

After a few months without many significant results, including an elimination to Nadal in Wimbledon, he reached the semifinals at the Stuttgart Open losing to eventual champion and World Number 8 Janko Tipsarević in three sets.
He then won his third career title at the Gstaad Open (his second trophy of the tournament) with a three set win over the same Janko Tipsarević.
At the 2012 Summer Olympics, he was knocked out in the first round of the men's singles by Jo-Wilfried Tsonga.
 He and teammate André Sá lost in the first round of the men's doubles to eventual gold medalists, the Bryan brothers.
 At the Kremlin Cup Bellucci reached his first final in a hard-court tournament, losing to Andreas Seppi.
In the Swiss Open he lost in three sets to World Number 1 Roger Federer in the second round of the tournament.
Next came a first round at the BNP Paribas Open, though by November his ranking position was 33.
Bellucci started 2012 reaching three second rounds in a row, with the Australian Open included, where he lost to Gaël Monfils.
In the Brasil Open, he reached the semifinals losing to Filippo Volandri. He then went to Indian Wells, where he managed to beat seed 20 Jürgen Melzer and walked over Russian Nikolay Davydenko to equalize his second best ever Masters 1000 campaign, reaching the fourth and losing to Roger Federer in three sets. At the Monte-Carlo Masters he defeated fifth seeded player David Ferrer to reach third round, where he lost to Robin Haase.
After a few months without many significant results, including an elimination to Nadal in Wimbledon, he reached the semifinals at the Stuttgart Open losing to eventual champion and World Number 8 Janko Tipsarević in three sets. He then won his third career title at the Gstaad Open (his second trophy of the tournament) with a three set win over the same Janko Tipsarević. At the 2012 Summer Olympics, he was knocked out in the first round of the men's singles by Jo-Wilfried Tsonga.  He and teammate André Sá lost in the first round of the men's doubles to eventual gold medalists, the Bryan brothers.  At the Kremlin Cup Bellucci reached his first final in a hard-court tournament, losing to Andreas Seppi. In the Swiss Open he lost in three sets to World Number 1 Roger Federer in the second round of the tournament. Next came a first round at the BNP Paribas Open, though by November his ranking position was 33.
Thomaz Bellucci