ATP - Madrid 04/27 09:00 24 [118] Thiago Monteiro v Stefanos Tsitsipas [7] 6-4,6-4
ATP - Madrid 04/25 11:15 23 [65] Dusan Lajovic v Thiago Monteiro [118] 4-6,3-6
ATP - Madrid 04/23 09:00 15 [133] Radu Albot v Thiago Monteiro [118] 6-7,6-1,4-6
ATP - Madrid 04/22 09:40 14 [226] Lucas Pouille v Thiago Monteiro [118] 6-4,4-6,4-6
Challenger - Oeiras 04/15 11:25 25 [255] Jaime Faria v Thiago Monteiro [113] 6-2,3-6,7-6
Challenger - Florianopolis 04/03 23:50 26 [110] Thiago Monteiro v Orlando Luz [335] 3-6,6-7
Challenger - Florianopolis 04/01 21:45 25 [110] Thiago Monteiro v Bogdan Bobrov [399] 6-2,6-4
Challenger - Sao Leopoldo 03/26 22:55 25 [371] Orlando Luz v Thiago Monteiro [110] 4-6,6-3,7-5
ATP - Miami 03/18 17:10 14 [150] Adam Walton v Thiago Monteiro [110] 6-7,7-6,6-4
Challenger - Santa Cruz 03/09 19:20 28 [113] Thiago Monteiro v Camilo Ugo Carabelli [127] 4-6,5-7
Challenger - Santa Cruz 03/09 14:00 27 [113] Thiago Monteiro v Pedro Sakamoto [336] 6-1,6-4
Challenger - Santa Cruz 03/06 21:05 26 [113] Thiago Monteiro v Valerio Aboian [478] 6-3,6-3
Challenger - Santa Cruz 03/04 23:10 25 [113] Thiago Monteiro v Edoardo Lavagno [241] 6-2,6-2
ATP - Rio de Janeiro 02/23 19:30 27 [118] Thiago Monteiro v Sebastian Baez [30] 4-6,6-1,2-6
ATP - Rio de Janeiro 02/22 22:00 26 [118] Thiago Monteiro v Felipe Meligeni Rodrigues Alves [151] 7-5,6-3
ATP - Rio de Janeiro 02/21 00:35 25 [2] Carlos Alcaraz v Thiago Monteiro [118] Retired
ATP - Buenos Aires 02/11 18:30 19 [151] Andrea Vavassori v Thiago Monteiro [119] 6-4,7-6
ATP - Buenos Aires 02/10 20:10 14 [148] Juan Manuel Cerundolo v Thiago Monteiro [119] 6-4,4-6,2-6
Davis Cup 02/03 13:45 168 [160] Elias Ymer v Thiago Monteiro [119] 6-4,4-6,2-6
Davis Cup 02/02 16:00 168 [364] Karl Friberg v Thiago Monteiro [119] 3-6,6-7
Challenger - Punta del Este 01/26 20:00 27 [180] Roman A Burruchaga v Thiago Monteiro [120] 6-3,5-7,7-6
Challenger - Punta del Este 01/25 23:15 26 [241] Facundo Bagnis v Thiago Monteiro [120] 2-6,3-6
Challenger - Punta del Este 01/24 00:30 25 [376] Federico Agustin Gomez v Thiago Monteiro [120] 1-6,4-6
Challenger - Brasilia 11/21 20:30 25 Thiago Monteiro v Fernando Romboli Cancelled
Challenger - Montevideo 11/19 22:00 29 [111] Facundo Diaz Acosta v Thiago Monteiro [131] Retired
Challenger - Montevideo 11/19 01:15 28 [112] Hugo Dellien v Thiago Monteiro [131] 6-7,6-1,3-6
Challenger - Montevideo 11/17 21:25 27 [131] Thiago Monteiro v Camilo Ugo Carabelli [144] 6-1,4-6,6-4
Challenger - Montevideo 11/15 17:00 26 [256] Santiago Rodriguez Taverna v Thiago Monteiro [131] 5-7,3-6
Challenger - Montevideo 11/14 15:00 25 [282] Murkel Dellien v Thiago Monteiro [131] 0-6,4-6
Challenger - Santa Fe 10/20 18:35 28 [146] Mariano Navone v Thiago Monteiro [126] 7-5,6-4

Thiago Moura Monteiro (Brazilian Portuguese: [tʃiˈaɡu mõˈtejɾu]; born 31 May 1994) is a Brazilian professional tennis player.

Monteiro has a career-high ATP singles ranking of world No. 61 achieved on 17 October 2022. He also has a career-high ATP doubles ranking of No. 144, achieved on 31 January 2022. He is currently the No. 2 Brazilian tennis player.

On the ITF Junior Circuit, Monteiro peaked in the rankings at No. 2 on 2 February 2012, with his biggest junior singles title being the Grade A, Copa Gerdau in Porto Alegre, Brazil, in 2011.

In his first ATP match, as a wildcard ranked world No. 338 in the ATP 500 Rio de Janeiro in February 2016, Monteiro upset No. 9 Jo-Wilfried Tsonga in the first round. In the second round, Monteiro lost to eventual champion Pablo Cuevas. In his next tournament, the ATP 250 São Paulo, Monteiro won two matches (against former World No. 9 Nicolás Almagro, and Daniel Muñoz de la Nava), losing again to eventual champion Cuevas in the quarterfinals.

On May 8, 2016, Monteiro won his first ATP Challenger title in Aix-en-Provence, France. He defeated Carlos Berlocq in the final.