In an effort to support Viet Nam's efforts to decentralize nutrition planning, A&T provided targeted assistance and capacity-building for 15 provincial plans for nutrition (PPNs). The study aimed to (i) assess PPN content and quality improvements 2009–2014, and (ii) explain processes through which change occurred. Results showed that targeted assistance and local advocacy can improve decentralized planning, with success dependent on policy and programming contexts and ability to overcome constraints around capacity, investment, data use and remnants of centralized planning. Provinces became more proactive and creative, but remained constrained by slow central approval processes and insufficient funding. This suggests that improvements occurred, particularly at the provincial level where A&T work was focused, but also suggests that there are continued challenges, particularly from the national level where more work might be done to relieve constraints on planning. The broader politics, however, will likely remain a limiting issue.