Sébastien Lareau (French pronunciation: [sebastjɛ̃ laʁo]; born April 27, 1973) is a former professional tennis player. He became the first Canadian to win a Grand Slam title by winning the 1999 US Open men's doubles with his American partner Alex O'Brien.

The right-handed Lareau achieved a career best singles ranking of world No. 76 in April 1995. He has a career ATP Tour event win–loss record of 99–137. Lareau's best singles tour results were:

• in 1995, the quarterfinals of the Philadelphia and St. Petersburg World Series events;
• in 1996, the fourth round of the Key Biscayne Super 9 event;
• in 1997, the quarterfinals of the Hong Kong World Series event;
• in 1998, the third round of the Australian Open; the semifinals of the Philadelphia, the quarterfinals of the Scottsdale, the semifinals of the Hong Kong, the quarterfinals of the Washington and Moscow World Series events;
• in 1999, the quarterfinals of the Tokyo Outdoor World Series event; and
• in 2001, the semifinals of the Memphis International Series Gold event.

Lareau reached a career-high doubles ranking of world No. 4 in October 1999. He won 16 doubles titles on the ATP Tour. His victories included the 1996 and 1998 Stuttgart Masters, the 1999 London Queen's Club International Series, the 1999 US Open, the 1999 Paris Indoor Tennis Masters, and the 1999 ATP Doubles Championships events, all partnering Alex O'Brien; the 1999 Washington International Series and 2000 Memphis International Series Gold events, partnering Justin Gimelstob; and the 2000 Montreal/Toronto Tennis Masters and Sydney Olympics, partnering compatriot Daniel Nestor. Lareau was also a finalist in the 1996 Australian Open and ATP Doubles Championships, 1997 Australian Open, both partnering O'Brien.

Result	Year	Tournament	Surface	Partner	Opponents	Score
Loss	1996	Australian Open	Hard	Alex O'Brien	Stefan Edberg Petr Korda	5–7, 5–7, 6–4, 1–6
Loss	1997	Australian Open	Hard	Alex O'Brien	Todd Woodbridge Mark Woodforde	6–4, 5–7, 5–7, 3–6
Win	1999	U.S. Open	Hard	Alex O'Brien	Mahesh Bhupathi Leander Paes	7–6(9–7), 6–4

Result	Year	Location	Surface	Partner	Opponents	Score
Gold	2000	Sydney	Hard	Daniel Nestor	Todd Woodbridge Mark Woodforde	5–7, 6–3, 6–4, 7–6

Result	W-L	Date	Tournament	Surface	Partner	Opponents	Score
Loss	1.	Apr 1994	Tokyo Outdoor, Japan	Hard	Patrick McEnroe	Henrik Holm Anders Järryd	6–7, 1–6
Loss	2.	Apr 1994	Seoul, South Korea	Hard	Kent Kinnear	Stéphane Simian Kenny Thorne	4–6, 6–3, 5–7
Loss	3.	Nov 1994	Antwerp, Belgium	Carpet	Hendrik Jan Davids	Jan Apell Jonas Björkman	6–4, 1–6, 2–6
Win	1.	May 1995	Seoul, South Korea	Hard	Jeff Tarango	Joshua Eagle Andrew Florent	6–3, 6–2
Win	2.	Oct 1995	Beijing, China	Carpet (i)	Tommy Ho	Dick Norman Fernon Wibier	7–6, 7–6
Loss	4.	Jan 1996	Australian Open, Melbourne	Hard	Alex O'Brien	Stefan Edberg Petr Korda	5–7, 5–7, 6–4, 1–6
Loss	5.	Jun 1996	Queen's Club, England	Grass	Alex O'Brien	Mark Woodforde Todd Woodbridge	3–6, 6–7
Loss	6.	Apr 1996	Doubles Championships, Hartford	Carpet (i)	Alex O’Brien	Mark Woodforde Todd Woodbridge	4–6, 7–5, 2–6, 6–7(3–7)
Win	3.	Oct 1996	Stuttgart Indoor, Germany	Carpet (i)	Alex O'Brien	Jacco Eltingh Paul Haarhuis	3–6, 6–4, 6–3
Loss	7.	Jan 1997	Australian Open, Melbourne	Hard	Alex O'Brien	Mark Woodforde Todd Woodbridge	6–4, 5–7, 5–7, 3–6
Win	4.	Mar 1997	Philadelphia, United States	Hard (i)	Alex O'Brien	Ellis Ferreira Patrick Galbraith	6–3, 6–3
Win	5.	Jul 1997	Los Angeles, United States	Hard	Alex O'Brien	Mahesh Bhupathi Rick Leach	7–6, 6–4
Loss	8.	Aug 1997	Montreal, Canada	Hard	Alex O’Brien	Mahesh Bhupathi Leander Paes	6–7, 3–6
Loss	9.	Aug 1997	New Haven, United States	Hard	Alex O'Brien	Mahesh Bhupathi Leander Paes	4–6, 7–6, 2–6
Win	6.	Apr 1998	Tokyo, Japan	Hard	Daniel Nestor	Olivier Delaître Stefano Pescosolido	6–4, 4–6, 6–4
Loss	10.	Jun 1998	Nottingham, England	Grass	Daniel Nestor	Justin Gimelstob Byron Talbot	5–7, 7–6, 4–6
Loss	11.	Aug 1998	New Haven, United States	Hard	Alex O'Brien	Wayne Arthurs Peter Tramacchi	6–7, 6–1, 3–6
Win	7.	Nov 1998	Stuttgart Indoor, Germany	Hard (i)	Alex O'Brien	Mahesh Bhupathi Leander Paes	6–3, 3–6, 7–5
Win	8.	Jan 1999	Sydney, Australia	Hard	Daniel Nestor	Patrick Galbraith Paul Haarhuis	6–3, 6–4
Loss	12.	Feb 1999	Memphis, United States	Hard (i)	Alex O’Brien	Todd Woodbridge Mark Woodforde	3–6, 4–6
Win	9.	Jun 1999	Queen's Club, England	Grass	Alex O'Brien	Todd Woodbridge Mark Woodforde	6–3, 7–6
Win	10.	Aug 1999	Washington, D.C., United States	Hard	Justin Gimelstob	David Adams John-Laffnie de Jager	7–5, 6–7, 6–3
Win	11.	Sep 1999	US Open, New York	Hard	Alex O'Brien	Mahesh Bhupathi Leander Paes	7–6(9–7), 6–4
Win	12.	Oct 1999	Shanghai, China	Hard	Daniel Nestor	Todd Woodbridge Mark Woodforde	7–5, 6–3
Win	13.	Nov 1999	Paris, France	Carpet (i)	Alex O'Brien	Jared Palmer Paul Haarhuis	7–6, 7–5
Win	14.	Nov 1999	Doubles Championships, Hartford	Carpet (i)	Alex O'Brien	Mahesh Bhupathi Leander Paes	6–3, 6–2, 6–2
Win	15.	Feb 2000	Memphis, United States	Hard (i)	Justin Gimelstob	Jim Grabb Richey Reneberg	6–2, 6–4
Loss	13.	Mar 2000	Copenhagen, Denmark	Carpet (i)	Jonas Björkman	Martin Damm David Prinosil	1–6, 7–5, 5–7
Loss	14.	May 2000	Orlando, United States	Clay	Justin Gimelstob	Leander Paes Jan Siemerink	3–6, 4–6
Win	16.	Aug 2000	Toronto, Canada	Hard	Daniel Nestor	Joshua Eagle Andrew Florent	6–3, 7–6(7–3)
Loss	15.	Aug 2001	Indianapolis, United States	Hard	Mahesh Bhupathi	Mark Knowles Brian MacPhie	6–7, 7–5, 4–6

• Sébastien Lareau at the Association of Tennis Professionals
• Sébastien Lareau at the International Tennis Federation
• Sébastien Lareau at the Davis Cup
• Sébastian Lareau – Tennis Canada