Ekaterina Sysoeva (Russian: Екатерина Сысоева, born 3 June 1981) is a former professional Russian tennis player.

In her career, Sysoeva won one doubles title on the WTA Tour, as well as three singles and ten doubles titles on the ITF Women's Circuit. She reached her career-high singles rank of world No. 178 on 12 August 2002. Her career-high in doubles is 87th, set on 14 October 2002.

Playing for Russia at the Fed Cup, Sysoeva has a win–loss 1–3.

Outcome	No.	Date	Tournament	Surface	Partner	Opponents	Score
Runner-up	1	22 February 1998	Bogotá, Colombia	Clay	Melissa Mazzotta	Janette Husárová Paola Suárez	6–3, 2–6, 3–6
Winner	1	14 July 2002	Palermo, Italy	Clay	Evgenia Kulikovskaya	Lubomira Bacheva Angelika Rösch	6–4, 6–3
Runner-up	2	22 July 2002	Sopot, Poland	Clay	Evgenia Kulikovskaya	Svetlana Kuznetsova Arantxa Sánchez Vicario	2–6, 2–6

Outcome	No.	Date	Tournament	Surface	Opponent	Score
Runner-up	1	17 October 1994	Moscow, Russia	Hard (i)	Olga Ivanova	2–6, 5–7
Winner	1	2 October 1995	Šiauliai, Lithuania	Hard	Nadia Streltsova	4–6, 6–2, 6–2
Runner-up	2	19 February 1996	Nürnberg, Germany	Carpet (i)	Jana Pospíšilová	3–6, 3–6
Runner-up	3	1 April 1996	Athens, Greece	Clay	Ulrike Priller	6–2, 3–6, 2–6
Runner-up	4	10 February 1997	Rogaška Slatina, Slovakia	Carpet (i)	Miriam Schnitzer	6–7(3), 4–6
Runner-up	5	17 May 1999	Pesaro, Italy	Clay	Susi Lohrmann	4–6, 2–6
Runner-up	6	16 July 2001	Frinton, England	Grass	Kristen van Elden	6–3, 4–6, 5–7
Winner	2	8 August 2001	Bath, England	Hard	Anna Floris	6–4, 6–0
Winner	3	13 August 2001	London, England	Hard	Natalia Egorova	6–4, 6–4
Runner-up	7	29 January 2002	Tipton, England	Hard (i)	Liu Nannan	6–4, 5–7, 4–6
Runner-up	8	29 April 2002	Maglie, Italy	Clay	Conchita Martínez Granados	1–6, 1–6
Runner-up	9	14 May 2002	Hatfield, England	Clay	Jane O'Donoghue	6–7(6), 1–6

Outcome	No.	Date	Tournament	Surface	Partner	Opponents	Score
Winner	1	19 May 1997	Sochi, Russia	Hard	Evgenia Kulikovskaya	Nino Louarsabishvili Kaoru Shibata	3–6, 6–3, 6–0
Winner	2	17 August 1998	Carrabba, Italy	Clay	Ayami Takase	Mireille Dittmann Natalie Dittmann	6–2, 6–0
Winner	3	5 October 1998	Batumi, Georgia	Hard	Evgenia Kulikovskaya	Amanda Hopmans Melanie Schnell	6–4, 3–6, 6–0
Runner-up	1	17 May 1999	Pesaro, Italy	Clay	Marijana Kovačević	Dragana Ilić Maja Matevžič	4–6, 3–6
Winner	4	21 June 1999	Tallinn, Estonia	Clay	Irina Kornienko	Minna Rautajoki Maria Wolfbrandt	6–1, 6–1
Runner-up	2	2 August 1999	Kharkiv, Ukraine	Clay	Zuzana Váleková	Nadejda Ostrovskaya Tatiana Perebiynis	7–5, 3–6, 3–6
Runner-up	3	9 August 1999	İstanbul, Turkey	Hard	Liudmila Nikoyan	Nadejda Ostrovskaya Ekaterina Paniouchkina	0–6, 2–6
Runner-up	4	27 September 1999	Tbilisi, Georgia	Clay	Nadejda Ostrovskaya	Maria Goloviznina Ekaterina Paniouchkina	0–6, 2–6
Runner-up	5	13 February 2000	Birmingham, England	Hard (i)	Natalia Egorova	Elena Bovina Anna Zaporozhanova	3–6, 4–6
Runner-up	6	8 May 2000	Swansea, Wales	Clay	Natalia Egorova	Nóra Köves Dragana Zarić	6–2, 4–6, 3–6
Winner	5	30 April 2001	Hatfield, England	Clay	Natalia Egorova	Elena Baltacha Nicola Trinder	6–3, 4–6, 6–1
Winner	6	7 May 2001	Swansea, Wales	Clay	Natalia Egorova	Maria Boboedova Emily Hewson	4–6, 7–6(5), 6–0
Runner-up	7	11 June 2001	Tallinn, Estonia	Clay	Natalia Egorova	Akiko Morigami Miho Saeki	2–6, 6–7(7)
Winner	7	8 August 2001	Bath, England	Hard	Natalia Egorova	Susi Bensch Anna Floris	7–6(4), 7–6(4)
Winner	8	9 October 2001	Cardiff, Wales	Carpet (i)	Natalia Egorova	Angelika Bachmann Vanessa Henke	6–4, 1–6, 6–2
Winner	9	5 February 2002	Redbridge, England	Hard (i)	Magda Mihalache	Helen Crook Sun Tiantian	4–6, 6–4, 6–4
Winner	10	14 May 2002	Hatfield, England	Clay	Irina Bulykina	Anna Hawkins Jane O'Donoghue	6–4, 4–6, 7–6(8)
Runner-up	8	1 July 2002	Orbetello, Italy	Clay	Evgenia Kulikovskaya	Maret Ani Andreea Ehritt-Vanc	3–6, 6–1, 1–6

• Ekaterina Sysoeva at the Women's Tennis Association
• Ekaterina Sysoeva at the International Tennis Federation
• Ekaterina Sysoeva at the Billie Jean King Cup (archived)