This paper presents an empirical investigation to measure the effect of managerial ability on earning quality on selected firms listed on Tehran Stock Exchange over the period 2007-2013. The proposed study uses data envelopment analysis to measure the relative efficiency of selected firms where Sales is considered as output and Cost of goods (COGS), Selling, General and Administrative Expenses (SG & A), Net Property Plant and Equipment (PPE), Net operating Leases (OpsLease), Research & Development (R & D), Purchased Good will (Goodwill) and Other intangible assets (OtherIntan) are considered as inputs. Earning quality in this survey consists of three parts of quality of accruals, earnings and earnings forecast persistence. The results of our survey have indicated that managerial ability influences positively on earning quality.