Markos Kalovelonis (Greek: Μάρκος Καλοβελώνης, Марк Георгиевич Каловелонис; born 18 May 1994) is a Greek-Russian tennis player.

Kalovelonis has a career high ATP singles ranking of World No. 445 achieved on 13 June 2016. He also has a career high ATP doubles ranking of World No. 178 achieved on 8 August 2023. Kalovelonis has won 21 ITF doubles titles.

Kalovelonis has represented Greece at the Davis Cup where he has a W/L record of 6–5. He also represented Greece in the ATP Cup in 2020, 2021 and 2022.

Kalovelonis is the son of former Greek tennis player, George Kalovelonis and Russian Karina Nazarenko. In 2014, Kalovelonis decided to represent Russia instead of Greece. In 2019, Kalovelonis switched back to represent Greece. He is fluent in Russian, Greek and English.

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Loss	0–1	Jan 2016	Kazakhstan, Aktobe	Futures	Hard (i)	Sergey Betov	3–6, 4–6
Loss	0–2	Jun 2016	Uzbekistan, Namangan	Futures	Hard	Chen Ti	4–6, 2–6
Loss	0–3	Jun 2018	United States, Rochester, New York	Futures	Clay	Alex Rybakov	1–6, 6–7(6–8)
Loss	0–4	Jul 2018	Estonia, Pärnu	Futures	Clay	Dragoș Nicolae Mădăraș	2–6, 3–6

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Loss	0–1	Apr 2012	Greece, Heraklion	Futures	Carpet	Charalampos Kapogiannis	Björn Propst Bastian Trinker	1–6, 3–6
Win	1–1	July 2013	Egypt, Sharm El Sheikh	Futures	Clay	Angelos Lenis	Karim Hossam Karim-Mohamed Maamoun	6–4, 3–6, [10–6]
Win	2–1	Sep 2013	Greece, Filippiada	Futures	Hard	Alexandros Jakupovic	Valentin Dimov Dinko Halachev	6–3, 6–3
Loss	2–2	Apr 2014	Uzbekistan, Karshi	Futures	Hard	Shonigmatjon Shofayziyev	Piotr Gadomski Adam Majchrowicz	5–7, 1–6
Win	3–2	Jun 2014	Turkey, Istanbul	Futures	Hard	Alexander Merino	Damian Farinola Darren Polkinghorne	3–6, 6–1, [10–8]
Loss	3–3	Aug 2014	Iran, Tehran	Futures	Clay	Amirvala Madanchi	Vinayak Sharma Kaza Vijay Sundar Prashanth	3–6, 4–6
Loss	3–4	Nov 2014	Greece, Heraklion	Futures	Hard	Alexandros Jakupovic	Ivan Bjelica Miljan Zekić	3–6, 6–7(4–7)
Win	4–4	Nov 2014	Greece, Heraklion	Futures	Hard	Alexandros Jakupovic	Sander Gillé Alexis Musialek	7–6(7–1), 7–6(7–4)
Loss	4–5	Nov 2014	Greece, Heraklion	Futures	Hard	Alexandros Jakupovic	Danilo Petrović Ilija Vucic	5–7, 2–6
Win	5–5	Mar 2015	Greece, Heraklion	Futures	Hard	Alexandros Jakupovic	Patrich Grigoriu Costin Pavăl	6–4, 6–2
Win	6–5	Apr 2015	Greece, Heraklion	Futures	Hard	Alexandros Jakupovic	Patrich Grigoriu Costin Pavăl	2–6, 7–5, [10–5]
Loss	6–6	Apr 2015	Egypt, Sharm El Sheikh	Futures	Hard	Lucas Miedler	Martin Fischer Jannis Liniger	4–6, 2–6
Win	7–6	Apr 2015	Greece, Heraklion	Futures	Hard	Alexandros Jakupovic	Joe Salisbury Joshua Ward-Hibbert	6–1, 6–2
Loss	7–7	May 2015	Croatia, Bol	Futures	Clay	Martin Beran	Gábor Borsos Levente Gödry	4–6, 5–7
Loss	7–8	Jun 2015	Uzbekistan, Andijan	Futures	Hard	Shonigmatjon Shofayziyev	Denis Matsukevich Denys Molchanov	6–2, 6–7(5–7), [12–14]
Loss	7–9	Jun 2015	Turkey, Istanbul	Futures	Hard	Temur Ismailov	Tuna Altuna Bradley Mousley	4–6, 4–6
Loss	7–10	Sep 2015	India, Chennai	Futures	Hard	Timur Khabibulin	Jeevan Nedunchezhiyan Vijay Sundar Prashanth	6–4, 3–6, [4–10]
Loss	7–11	Sep 2015	India, Chennai	Futures	Hard	Kunal Anand	Xin Gao Bowen Ouyang	2–6, 7–5, [9–11]
Loss	7–12	Oct 2015	Kazakhstan, Shymkent	Futures	Clay	Aleksandar Lazov	Ivan Gakhov Aleksandre Metreveli	6–7(4–7), 3–6
Win	8–12	Dec 2015	Cyprus, Lamaca	Futures	Hard	Konstantinos Economidis	Andrés Artuñedo Martinavarro Steven Diez	4–6, 6–3, [10–5]
Loss	8–13	Apr 2016	Kazakhstan, Shymkent	Futures	Clay	Aleksandre Metreveli	Saniar Fayziev Andrei Vasilevski	2–6, 4–6
Win	9–13	Apr 2016	Kazakhstan, Shymkent	Futures	Clay	Aleksandre Metreveli	Miki Janković Andrei Vasilevski	6–4, 6–1
Win	10–13	May 2016	Uzbekistan, Andijan	Futures	Hard	Sriram Balaji	Roman Khassanov Vitaly Kozyukov	6–3, 6–4
Loss	10–14	Aug 2016	Belarus, Minsk	Futures	Hard	Vasko Mladenov	Yaraslav Shyla Dzmitry Zhyrmont	6–7(8–10), 3–6
Loss	10–15	Oct 2016	Greece, Heraklion	Futures	Hard	Filipp Kekercheni	Adrian Andrzejczuk Mateusz Smolicki	7–6(7–1), 6–7(5–7), [9–11]
Loss	10–16	Dec 2016	Cyprus, Lamaca	Futures	Hard	Alexandre Müller	Lucas Miedler Maximilian Neuchrist	3–6, 6–1, [5–10]
Loss	10–17	Mar 2017	Greece, Heraklion	Futures	Hard	Temur Ismailov	Hunter Callahan Nicholas S. Hu	6–4, 1–6, [11–13]
Win	11–17	Jul 2017	Russia, Kazan	Futures	Hard	Evgenii Tiurnev	Alexander Boborykin Timur Kiyamov	6–2, 7–6(10–8)
Loss	11–18	Aug 2017	Russia, Kazan	Futures	Hard	Alexander Pavlioutchenkov	Daniiar Duldaev Denis Yevseyev	6–7(2–7), 4–6
Win	12–18	Apr 2018	Greece, Heraklion	Futures	Hard	Yaraslav Shyla	Erik Crepaldi Petr Michnev	6–4, 7–6(7–5)
Loss	12–19	Jul 2018	Estonia, Pärnu	Futures	Clay	Denis Klok	Marc Dijkhuizen Bart Stevens	4–6, 2–6
Win	13–19	Sep 2018	Egypt, Cairo	Futures	Clay	Alexander Erler	Anirudh Chandrasekar Aryan Goveas	6–4, 7–6(7–3)
Loss	13–20	Nov 2018	Greece, Heraklion	Futures	Hard	Petros Tsitsipas	Vit Kopriva David Pichler	2–6, 6–4, [7–10]
Win	14–20	Dec 2018	Turkey, Antalya	Futures	Clay	Sanjar Fayziev	Tadeas Paroulek Oleg Prihodko	7–5, 3–6, [10–6]
Loss	14–21	Apr 2019	M25 Andijan, Uzbekistan	World Tennis Tour	Hard	Grigoriy Lomakin	Timur Khabibulin Vladyslav Manafov	5–7, 1–6
Win	15–21	Jun 2019	M15 Akko, Israel	World Tennis Tour	Hard	Michail Pervolarakis	Julian Bradley Florian Lakat	6–7(9–11), 6–4, [10–6]
Loss	15–22	Aug 2019	M15 Moscow, Russia	World Tennis Tour	Clay	Sergey Fomin	Alen Avidzba Ivan Davydov	6–3, 1–6, [7–10]
Win	16–22	Mar 2021	M15 Antalya, Turkey	World Tennis Tour	Clay	Sanjar Fayziev	Vlad Andrei Dancu Gabriel Donev	5–7, 7–6(7–3), [10–7]
Win	17–22	May 2021	M15 Tbilisi, Georgia	World Tennis Tour	Hard	Sanjar Fayziev	Aleksandre Bakshi Zura Tkemaladze	6–4, 3–6, [10–5]
Loss	17–23	May 2021	M15 Shymkent, Kazakhstan	World Tennis Tour	Clay	Sanjar Fayziev	Yan Bondarevskiy Grigoriy Lomakin	3–6, 4–6
Win	18–23	Jul 2021	M25 Nur-Sultan, Kazakhstan	World Tennis Tour	Hard	Sanjar Fayziev	Oleksii Krutykh Vladyslav Manafov	7–6(7–1), 6–3
Loss	18–24	Sep 2021	M25 Johannesburg, South Africa	World Tennis Tour	Hard	Michail Pervolarakis	Alec Beckley Vaughn Hunter	1–6, 6–7(5–7)
Win	19–24	Oct 2021	M25 Nur-Sultan, Kazakhstan	World Tennis Tour	Hard (i)	Sanjar Fayziev	Aliaksandr Liaonenka Yan Sabanin	6–7(7–9), 6–4, [10–7]
Win	20–24	Nov 2021	M15 Heraklion, Greece	World Tennis Tour	Hard	Sanjar Fayziev	William Ma Alexis Musialek	6–4, 6–1
Loss	20–25	Dec 2021	Antalya, Turkey	Challenger	Clay	Sanjar Fayziev	Hsu Yu-hsiou Oleksii Krutykh	1–6, 6–7(5–7)
Loss	20–26	Jan 2022	M25 Cairo, Egypt	World Tennis Tour	Clay	David Pichler	Yu Hsiou Hsu Neil Oberleitner	6–7(5–7), 4–6
Win	21–26	Mar 2022	M25 Antalya, Turkey	World Tennis Tour	Clay	Sanjar Fayziev	Moez Echargui Alexander Weis	6–2, 6–4
Loss	21–27	Mar 2022	Oeiras, Portugal	Challenger	Clay	Sanjar Fayziev	Nuno Borges Francisco Cabral	3–6, 0–6
Win	22–27	May 2022	Shymkent, Kazakhstan	Challenger	Clay	Sanjar Fayziev	Mikael Torpegaard Kaichi Uchida	6–7(3–7), 6–4, [10–4]
Win	23–27	Aug 2023	M25 Jakarta, Indonesia	World Tennis Tour	Hard	Khumoyun Sultanov	Palaphoom Kovapitukted Manish Sureshkumar	4–6, 7–5, [10–7]
Loss	23–28	Oct 2023	Shenzhen, China	Challenger	Hard	Mikalai Haliak	Gao Xin Wang Aoran	4–6, 2–6
Loss	23–29	Nov 2023	M25 Heraklion, Greece	World Tennis Tour	Hard	Sergis Kyratzis	Simon Freund Vladyslav Orlov	7–6(7–4), 4–6, [7–10]
Loss	23–30	Jun 2024	Lyon, France	Challenger	Clay	Vladyslav Orlov	Manuel Guinard Grégoire Jacq	6–4, 3–6, [6–10]

• Markos Kalovelonis at the Association of Tennis Professionals
• Markos Kalovelonis at the International Tennis Federation
• Markos Kalovelonis at the Davis Cup