A large theoretical and empirical literature examines the role of the accounting information quality (Bushman et al., 2001; Bushman and Smith, 2001; Bagaeva, 2008; Chan et al., 2009; Chan and Lee, 2009; Zhiying et al., 2012; Ran et al., 2015). One line of research (Biddle and Hilary, 2006; McNichols and Stubben, 2008; Biddle et al., 2009; Chen et al., 2011) suggests that higher quality information enables managers to identify better investment opportunities. Several studies also propose that auditor specialization can be used to reduce the information asymmetry problems (Almutairi et al., 2009; DeBoskey et al., 2012; DeBoskey and Jiang, 2012; Yaghoobnezhada et al., 2014): A specialist’s knowledge of the industry can be developed through vast auditing experience, specialized staff training, and large investments in information technology. This industry-specific knowledge allows specialist auditors to provide higher quality audit service by reducing the information asymmetry through their greater ability to detect significant anomalies. Theoretical models (Balsam et al., 2003; Lai, 2011) predict that, despite the limited evidence, a highly acquired audit quality is extremely useful for improving investment efficiencies, especially with respect to overinvestment. Based on these premises, the main purpose of this paper is to combine these two mechanisms and analyze the effect of the accounting information quality (AIQ) and the auditor specialization on investment efficiency.