Mega-regional trade agreements (MRTAs) have appeared in response to the prolonged stagnation of the multilateral trading system ruled by the World Trade Organization (WTO). Although this issue has stimulated research in international integration, the specifics of MRTAs have not yet been sufficiently investigated. This article therefore assesses the multilateralization potential of regional commitments using the example of the Trans-Pacific Partnership (TPP). It includes commitments in market access liberalization made in regional trade agreements (RTAs) and in intraregional agricultural trade liberalization under the TPP.The central research problem is to identify the regional liberalization commitments that might be promoted to the level of the WTO. The authors use the methodology devised by the Organisation for Economic Co-operation and Development for assessing the potential multilateralization. RTA and MRTA commitments are grouped in two policy areas: WTO-plus (going beyond the normal provisions of the WTO) and WTO-beyond (dealing with issues going beyond the WTO). The TTP is scrutinized in the context of intraregional agricultural trade liberalization.MRTAs can raise regional commitments to the global level because of their large membership, regulatory transparency and high levels of implementation. The multilateralization of regional agreements is expected in services and investments as well as in various aspects of technical regulation. The key features of implementing RTA’s WTO-plus and WTO-beyond commitments in intraregional agricultural trade are discussed. Most RTAs have liberalized tariffs beyond the WTO Agreement on Agriculture (WTO-plus), but only a few have strengthened disciplines in non-tariff barriers and implemented WTO-beyond commitments for export restrictions and export subsidies. The TPP parties are a diverse group in terms of involvement in global agricultural trade and applied tariffs on agriculture and food. The TPP provides the record in eliminating tariffs for agricultural products while keeping a number of exceptions for sensitive products and long implementation periods. Agricultural market liberalization under the TPP is achieved mostly through eliminating tariffs than by renewing non-tariff barriers. The TPP parties share the objective of implementing WTO commitments by supporting the global agricultural trade reform on export subsidies and export bans, and agree to incorporate WTO-plus and WTO-beyond obligations.