The main objective of this study is to identify an indicator for the assessment of institutional thickness amongst various possible proxy measures in the Turkish context. Data for the creation of this indicator were collected at the provincial level after theorizing about studies of institutional thickness. The database includes the amount of public investment, the amount of investment incentives, the amount of municipality expenditure, the number of SMEs investment incentive certificates, the number of NGOs, the number of public buildings, the public knowledge creation variable, and the collaborative knowledge creation variable of Turkey. These variables are correlated and examined by taking their component and rotated component matrixes of them. The public knowledge creation indicator is identified as the most significant variable to describe the Turkish institutional setting. However, some commonly thought indicators remain insignificant in the analysis which raises the importance of country specific analysis. Key words: Institutional thickness, innovation systems, Turkish regional growth. INTRODUCTION Institutions are the main players of the innovation systems literature and they have received a lot of attention in the field of business management, economics and economic geography (Freeman, 1987; Cooke, 1990; Lundvall, 1992; Malerba, 2002). After the emergence of the flexible-production systems, institutions have been affiliated with the concepts of ‘learning regions’ (Asheim, 1997; Lundvall, 1992; Maskell et al., 1998) and they have changed the direction of economic development to more ‘social’ and ‘cultural’ issues such as social consensus, institutional support for local business, innovation, skill formation and the circulation of ideas (Amin and Thrift, 1994; Asheim, 1996). Geography has a particular impor-tance in the process of innovation and learning since these social and cultural dimensions are localized in specific places. Considering the ‘place-centredness’ of these dimen-sions, Amin and Thrift (1994: 2) emphasize the role of certain institutions, ranging from strong local institutional presence through to the strength of shared rules and knowledge, to form the social and cultural basis of the economic success of the regions. They provide a list of the organizational components to describe the institu-tional thickness of a locality such as a strong institutional presence ranging from firms, training centres, government agencies, trade associations; high levels of interaction amongst the institutional network in the locality; structures of domination and patterns of coalition; and a mutual awareness of an ‘industrial purpose’ amongst institutions (Amin and Thrift, 1994, 1995). In the most appropriate combination of these four determinants of institutional thickness, the concept is expected to have institutional persistence; achievement of commonly held knowledge; institutional flexibility; a high innovation capacity; trust and reciprocity; and a plethora of diverse institutions to mobilise regions effectively (Henry and Pinch, 2001). However, the concept of institutional thickness still remains as a very broad issue to conceptualize because it is essentially intangible. Some studies suggest that it is key to understanding the workings of the global economy (Amin and Thrift, 1994, 1995; Henry and Pinch, 2001; Keeble et al., 1999; Raco, 1998; Sydow and Staber, 2002), and that it enables us to understand local and