In July 2013, the EU and the US started negotiations on a Transatlantic Trade and Investment Partnership T-TIP. This agreement aims at creating growth and jobs in both economies. Various assessment studies have been carried out to evaluate the overall impact of such an agreement. The objective of this thesis is to analyze the impact of a T-TIP on the global dairy sector. GSIM, a partial equilibrium model, has been applied for the analysis. The results indicate that global trade in dairy products increases in a T-TIP. In a complete liberalization scenario the US value of trade with the EU increases by more than 150% while the EU trade value with the US rises by around 52%. Furthermore, the domestic prices in the EU and the US decrease by 4% respectively, 9%. The net welfare impact is positive for the EU and the US, whereas the rest of the world is negatively affected. Thus, policy recommendations pro or against a T-TIP depend on weights given to national and global welfare impacts.