Singles
2021 Iași Open
Final
Champion	Zdeněk Kolář
Runner-up	Hugo Gaston
Score	7–5, 4–6, 6–4
Events
Singles Doubles
← 2020 · Iași Open · 2022 →

Carlos Taberner was the defending champion^[1] but chose not to defend his title.

Zdeněk Kolář won the title after defeating Hugo Gaston 7–5, 4–6, 6–4 in the final.

	Semifinals							Final
	1	Hugo Gaston	7	77
	4	Felipe Meligeni Alves	5	64
								1	Hugo Gaston	5	6	4
								5	Zdeněk Kolář	7	4	6
	Q	Miljan Zekić	5	6	2
	5	Zdeněk Kolář	7	2	6

	First round							Second round							Quarterfinals							Semifinals
	1	H Gaston	6	3	6
		N Fatić	1	6	1			1	H Gaston	4	6	77
		M Pecotić	4	6	6				M Pecotić	6	4	65
		R Ortega Olmedo	6	0	1										1	H Gaston	77	6
		D Ajduković	6	6												D Ajduković	64	2
	WC	C Crețu	3	2					D Ajduković	6	6
	Q	A Lazarov	6	3	2			6	M Copil	4	4
	6	M Copil	3	6	6																	1	H Gaston	7	77
	4	F Meligeni Alves	7	6																		4	F Meligeni Alves	5	64
		I Sijsling	5	2				4	F Meligeni Alves	6	6
	WC	Ștefan Paloși	4	4				PR	M Donati	3	3
	PR	M Donati	6	6											4	F Meligeni Alves	6	3	6
		N Sánchez Izquierdo	3	6	2										8	D Kuzmanov	0	6	3
	WC	ND Ionel	6	4	6			WC	ND Ionel	6	3	4
		P Krstin	2	2				8	D Kuzmanov	2	6	6
	8	D Kuzmanov	6	6

	First round							Second round							Quarterfinals							Semifinals
	7	M Janvier	3	64
	Q	M Zekić	6	77				Q	M Zekić	6	77
	Alt	H Casanova	6	6				Alt	H Casanova	3	63
		N Serdarušić	4	4											Q	M Zekić	7	6
		T Gabashvili	5	6	5											L Miedler	5	2
		L Miedler	7	4	7				L Miedler	77	6
		A Andreev	6	1	6				A Andreev	65	1
	3	A Müller	4	6	3																	Q	M Zekić	5	6	2
	5	Z Kolář	6	7																		5	Z Kolář	7	2	6
	Q	David Poljak	2	5				5	Z Kolář	6	6
		A Dougaz	6	77					A Dougaz	2	3
	LL	B Bobrov	4	64											5	Z Kolář	6	6
	Q	Dan Alexandru Tomescu	4	3												R Bonadio	4	4
		FC Jianu	6	6					FC Jianu	65	2
		R Bonadio	77	6					R Bonadio	77	6
	2	E Couacaud	65	3

• Main draw
• Qualifying draw