“…There are studies documenting positive relationship (Liu and Anbumozhi, 2009;Düzer and Önce, 2017;Temiz and Acar, 2018;Güngör and Dincel, 2018;Yıldırım et al, 2018;Atasel et al, 2020), negative relationship (Jennifer Ho and Taylor, 2007) and there is no relationship between two concepts (Siregar and Bachtiar, 2010;Altinay et al, 2017;Özmen et al, 2020). As for the strand of literature investigating the relationship between releasing sustainability reports, having external assurance and firms' corporate governance mechanism, studies document that there is a positive and significant relationship between firms' corporate governance and sustainability reporting that reduces the agency cost and information asymmetry (Singh et al Davidson, 2003;Henry, 2010;Rashid, 2013;Garanina and Kaikova, 2016;Tuan, 2019;Nguyen et al, 2020;Ayunitha et al, 2021). In this context, many studies provide evidence documenting that there is a positive relationship between sustainability reporting/external assurance and firms' board of directors characteristics such as board independence, board gender diversity, CEO-chairman separation and board size (Kolk and Perego, 2010;Allegrini and Greco, 2013;Cho et al , 2014;Chen et al, 2014;Cheng et al, 2015;Liao et al, 2018;Al-Shaer and Zaman, 2019;Vitolla et al, 2020;Acar et al, 2021;Hichri, 2022;Dobija et al, 2022).…”