Maria Sharapova defeated Jelena Janković in the final, 4–6, 7–6^(7–3), 6–3 to win the women's singles tennis title at the 2011 Cincinnati Masters.

Kim Clijsters was the reigning champion, but withdrew due to an abdominal injury.

The top eight seeds received a bye into the second round.

	Quarterfinals							Semifinals							Final
		Nadia Petrova	5	1
	9	Andrea Petkovic	7	6
								9	Andrea Petkovic	64	1
								13	Jelena Janković	77	6
	16	Peng Shuai
	13	Jelena Janković	w/o
															13	Jelena Janković	6	63	3
															4/WC	Maria Sharapova	4	77	6
	10	Samantha Stosur	3	2
	4/WC	Maria Sharapova	6	6
								4/WC	Maria Sharapova	2	6	6
								2	Vera Zvonareva	6	3	3
		Daniela Hantuchová	3	66
	2	Vera Zvonareva	6	78

	First round							Second round							Third round							Quarterfinals
								1	C Wozniacki	4	5
	WC	C McHale	7	4	6			WC	C McHale	6	7
		T Pironkova	5	6	1										WC	C McHale	3	3
		R Vinci	3	6	4											N Petrova	6	6
		N Petrova	6	0	6				N Petrova	6	77
	Q	A Glatch	0	2				15	A Ivanovic	3	64
	15	A Ivanovic	6	6																			N Petrova	5	1
	9	A Petkovic	5	77	6																	9	A Petkovic	7	6
		J Gajdošová	7	65	2			9	A Petkovic	6	6
	LL	S Arvidsson	0	77	6			LL	S Arvidsson	2	4
	Q	M Niculescu	6	64	3										9	A Petkovic	6	6
		R Marino	5	2											6	P Kvitová	3	3
	Q	C Scheepers	7	6				Q	C Scheepers	63	3
								6	P Kvitová	77	6

	First round							Second round							Third round							Quarterfinals
								LL	P Parmentier	2	3
		S Lisicki	4	64					S Pe'er	6	6
		S Pe'er	6	77												S Pe'er	3	2
	WC	S Stephens	1	5											16	S Peng	6	6
		S Errani	6	7					S Errani	2	4
		G Dulko	3	6	4			16	S Peng	6	6
	16	S Peng	6	4	6																	16	S Peng
	13	J Janković	6	6																		13	J Janković	w/o
		I Benešová	0	3				13	J Janković	4	6	6
		J Görges	2	6	4			Q	J Zheng	6	3	1
	Q	J Zheng	6	1	6										13	J Janković	6	5	6
	Q	S Zhang	62	3											7	F Schiavone	3	7	4
		M Kirilenko	77	6					M Kirilenko	5	6	4
								7	F Schiavone	7	3	6

	First round							Second round							Third round							Quarterfinals
								5	N Li	6	6
		L Šafářová	6	6					L Šafářová	3	4
		K Zakopalová	2	2											5	N Li	4	6	4
		L Hradecká	3	65											10	S Stosur	6	3	6
		S Williams	6	77					S Williams
	Q	E Daniilidou	3	1				10	S Stosur	w/o
	10	S Stosur	6	6																		10	S Stosur	3	2
	14	S Kuznetsova	6	6																		4/WC	M Sharapova	6	6
	Q	J Craybas	3	4				14	S Kuznetsova	4	6	6
	Q	P Cetkovská	2	6	6			Q	P Cetkovská	6	3	4
		A Medina Garrigues	6	2	2										14	S Kuznetsova	2	3
	Q	A Rodionova	6	6											4/WC	M Sharapova	6	6
	WC	P Hercog	0	0				Q	A Rodionova	1	3
								4/WC	M Sharapova	6	6

	First round							Second round							Third round							Quarterfinals
								8	M Bartoli	6	6
		A Morita	2	6	2			PR	A Bondarenko	1	2
	PR	A Bondarenko	6	4	6										8	M Bartoli	3	7	3
		D Hantuchová	6	4												D Hantuchová	6	5	6
		L Domínguez Lino	3	1r					D Hantuchová	6	6
		F Pennetta	2	6	6				F Pennetta	3	4
	12	A Pavlyuchenkova	6	3	3																		D Hantuchová	3	66
	17	Y Wickmayer	6	6																		2	V Zvonareva	6	78
	Q	B Jovanovski	3	4				17	Y Wickmayer	6	2	2
		E Vesnina	6	65	0			Q	P Martić	3	6	6
	Q	P Martić	3	77	6										Q	P Martić	2	2
	LL	MJ Martínez Sánchez	5	3											2	V Zvonareva	6	6
		E Makarova	7	6					E Makarova	3	0
								2	V Zvonareva	6	6

• Main Draw