This study looks at the current level of liberalization in services sectors among the OECD members and investigates the impacts of services liberalization on trade and GDP growth. In doing so, the gravity model and computable general equilibrium model are applied for the analytical work and the services trade restrictiveness index (STRI) developed by the OECD is included as an indicator for the liberalization of services sectors. This research provides four main outcomes as follows.
 First, the barriers in the services sectors consist mainly of the restrictions related to foreign entry and the movement of people among five policy areas of the STRI. In other words, measures on market access have been kept and remained more persistently than other measures.
 Second, the extensive differences in regulations and restrictions across countries are found in most services sectors. Since services trade liberalization does not mean the complete abolition of regulations or restrictions in services, one of the effective ways to reduce trade costs in services is to reasonably harmonize the regulatory differences across countries.
 Third, the empirical analysis using the gravity model provides an interesting outcome that domestic policy areas such as barriers to competition in public sectors or regulatory consistency and transparency have a relatively larger impact on trade than other policy areas such as restrictions on foreign entry or movement of people. Notwithstanding the domestic policy areas account less for the restrictions in services sectors, the empirical result implies that the regulatory reforms in those areas have a larger economic impact.
 Fourth, the CGE analysis using GTAP based on the TiSA(Trade in Services Agreement) scenario provides the outcome that further services liberalization lead most economies to grow faster in terms of GDP. Especially, relatively faster growth is identified in developing and emerging economies rather than advanced economies. Moreover, the output growth in manufacturing sectors in developing and emerging economies is more significant than in advanced economies as well.