Doubles
2021 Zagreb Open
Final
Champions	Evan King Hunter Reese
Runners-up	Andrey Golubev Aleksandr Nedovyesov
Score	6–2, 7–6(7–4)
Events
Singles Doubles
← 2011 · Zagreb Open · 2022 →

This was the first edition of the tournament since 2011.^[1]

Evan King and Hunter Reese won the title after defeating Andrey Golubev and Aleksandr Nedovyesov 6–2, 7–6^(7–4) in the final.

	First round							Quarterfinals							Semifinals							Final
	1	A Golubev A Nedovyesov	6	2	[10]
		S Báez T Seyboth Wild	1	6	[0]			1	A Golubev A Nedovyesov	w/o
		D Popko A Tabilo	4	6	[10]				D Popko A Tabilo
		N Pasha M Schnur	6	1	[7]										1	A Golubev A Nedovyesov	77	6
	Alt	JM Cerúndolo R Olivo														S Walków J Zieliński	65	4
		J Jung G Soeda	w/o						J Jung G Soeda	3	4
		S Walków J Zieliński	6	6					S Walków J Zieliński	6	6
	WC	D Golubev E Tiurnev	0	2																		1	A Golubev A Nedovyesov	2	64
		R Jebavý A Martin	66	714	[11]																	3	E King H Reese	6	77
		S Balaji R Ramanathan	78	612	[9]				R Jebavý A Martin	6	3	[4]
	WC	Z Babić F Fallert	77	4	[8]			3	E King H Reese	2	6	[10]
	3	E King H Reese	64	6	[10]										3	E King H Reese	710	3	[10]
	WC	D Ajduković F Ninčević	6	77											2	R Arneodo A Olivetti	68	6	[5]
		F Coria E Gómez	3	62				WC	D Ajduković F Ninčević	5	4
		L Margaroli M Safwat	3	65				2	R Arneodo A Olivetti	7	6
	2	R Arneodo A Olivetti	6	77

• Main draw