EXHIBIT 12.1

Corporate Office Properties Trust

Ratio of Earnings to Combined Fixed Charges and Preferred Share Dividends

(Dollars in thousands)

		Year Ended December 31,
		2016				2015				2014				2013				2012
Earnings:
(Loss) income from continuing operations before equity in income (loss) of unconsolidated entities and income taxes		$	(26,419	)		$	120,812			$	34,590			$	36,704			$	8,894
Gain on sales of real estate, excluding discontinued operations		40,986				68,047				10,671				9,016				21
Combined fixed charges and preferred share dividends (from below)		104,541				111,737				115,842				120,307				133,345
Amortization of capitalized interest		2,715				2,591				2,374				1,977				1,798
Distributed income of equity investees		732				361				225				1,857				—
Subtract:
Capitalized interest (from below)		(5,723		)		(7,151		)		(6,065		)		(8,785		)		(13,903		)
Preferred share dividends included in fixed charges		(14,297		)		(14,210		)		(15,939		)		(19,971		)		(20,844		)
Preferred unit distributions included in fixed charges		(660		)		(660		)		(660		)		(660		)		(660		)
Preferred distributions of other consolidated entities		(16		)		(16		)		(16		)		(16		)		(16		)
Total earnings		$	101,859			$	281,511			$	141,022			$	140,429			$	108,635
Combined Fixed Charges and Preferred Share Dividends:
Combined fixed charges and preferred share dividends:
Interest expense on continuing operations		$	83,163			$	89,074			$	92,393			$	82,010			$	86,401
Interest expense on discontinued operations		—				—				—				8,221				10,397
Capitalized interest (internal and external)		5,723				7,151				6,065				8,785				13,903
Amortization of debt issuance costs-capitalized		—				8				186				144				649
Interest included in rental expense		682				618				583				500				475
Preferred share dividends		14,297				14,210				15,939				19,971				20,844
Preferred unit distributions		660				660				660				660				660
Preferred distributions of other consolidated entities		16				16				16				16				16
Total combined fixed charges and preferred share dividends		$	104,541			$	111,737			$	115,842			$	120,307			$	133,345
Ratio of earnings to combined fixed charges and preferred share dividends		0.97				2.52				1.22				1.17				0.81
Deficiency		$	2,682															$	24,710

For purposes of calculating the above ratios, earnings were computed by adding fixed charges (excluding capitalized interest), gain on sales of real estate (excluding discontinued operations) amortization of capitalized interest and distributed income of equity investees to income from continuing operations before noncontrolling interests, equity in income of unconsolidated entities and income taxes. Fixed charges consist of interest costs and capitalized amortization of debt issuance costs.