Menelaos Efstathiou (Greek: Μενέλαος Ευσταθίου; born 2 March 1999) is a Cypriot tennis player.

Efstathiou has a career high ATP singles ranking of No. 964 achieved on 15 August 2022. He also has a career high ATP doubles ranking of No. 1138 achieved on 15 August 2022.

Efstathiou has represented Cyprus in the Davis Cup, where he has a W/L record of 5–6.

Efstathiou reached the quarterfinals of the 2017 Australian Open boys' singles championships.

Efstathiou has a career high ITF junior combined ranking of world No. 42 achieved on 27 March 2017.

Efstathiou's manager is Socrates Polycarpou.^[1]

• indicates the outcome of the Davis Cup match followed by the score, date, place of event, the zonal classification and its phase, and the court surface.

Rubber outcome	No.	Rubber	Match type (partner if any)	Opponent nation	Opponent player(s)	Score
1–4; 3–5 February 2017; National Tennis Centre, Nicosia, Cyprus; Europe/Africa Zone Group II first round; hard surface
Defeat	1	II	Singles	Turkey	Marsel İlhan	7–5, 6–1, 4–6, 6–7(5–7), 4–6
1–4; 7–9 April 2017; National Tennis Centre, Nicosia, Cyprus; Europe/Africa Zone Group II relegation play-off; hard surface
Defeat	2	I	Singles	Tunisia	Malek Jaziri	2–6, 3–6, 5–7
3–0; 4 April 2018; Tennis Club Lokomotiv, Plovdiv, Bulgaria; Europe Zone Group III Pool B round robin; clay surface
Victory	3	II	Singles	Andorra	Èric Cervós Noguer	6–0, 6–0
2–1; 5 April 2018; Tennis Club Lokomotiv, Plovdiv, Bulgaria; Europe Zone Group III Pool B round robin; clay surface
Defeat	4	II	Singles	San Marino	Marco De Rossi	4–6, 5–7
1–2; 6 April 2018; Tennis Club Lokomotiv, Plovdiv, Bulgaria; Europe Zone Group III Pool B round robin; clay surface
Defeat	5	II	Singles	Monaco	Lucas Catarina	7–5, 1–6, 2–6
0–2; 7 April 2018; Tennis Club Lokomotiv, Plovdiv, Bulgaria; Europe Zone Group III 3rd-4th playoff; clay surface
Defeat	6	II	Singles	Macedonia	Dimitar Grabul	1–6, 7–5, 6–7(5–7)
3–0; 15 July 2019; Centro Tennis Cassa di Risparmio, City of San Marino, San Marino; Europe Zone Group IV Pool A round robin; clay surface
Victory	7	I	Singles	Iceland	Birkir Gunnarsson	6–1, 6–2
3–0; 16 July 2019; Centro Tennis Cassa di Risparmio, City of San Marino, San Marino; Europe Zone Group IV Pool A round robin; clay surface
Victory	8	I	Singles	Armenia	Artur Soghoyan	6–1, 6–1
3–0; 18 July 2019; Centro Tennis Cassa di Risparmio, City of San Marino, San Marino; Europe Zone Group IV Pool A round robin; clay surface
Victory	9	I	Singles	Albania	Martin Muedini	6–0, 6–1
3–0; 19 July 2019; Centro Tennis Cassa di Risparmio, City of San Marino, San Marino; Europe Zone Group IV Pool A round robin; clay surface
Victory	10	I	Singles	Liechtenstein	Robin Forster	6–0, 6–1
2–1; 20 July 2019; Centro Tennis Cassa di Risparmio, City of San Marino, San Marino; Europe Zone Group IV promotional playoff; clay surface
Defeat	11	I	Singles	Ireland	Simon Carr	3–6, 1–6

Outcome	No.	Date	Tournament	Surface	Partner	Opponent	Score
Victory	1.	2 June 2017	City of San Marino, San Marino	Clay	Eleftherios Neos	Florent Diep Thomas Oger	5–7, 6–2, [10–5]
Victory	2.	1 June 2019	Budva, Montenegro	Clay	Eleftherios Neos	Lucas Catarina Romain Arneodo	6–1, 7–5

• Menelaos Efstathiou at the Association of Tennis Professionals
• Menelaos Efstathiou at the International Tennis Federation
• Menelaos Efstathiou at the Davis Cup