In this brief, we describe what is involved in undertaking a sectoral assessment of tree seed and seedling delivery systems. This assessment is a starting point for improving the current poor situation for tree seed and seedling supply that typically prevails. While there is no one-size-fits-all approach, elements of general relevance for assessment have been identified. Surveys that determine the germplasm that is available and is being planted are important. The mapping of the stakeholders involved in the sector to describe the major models of supply is also key. Assessing the policy and regulatory landscape around supply, the capacity of the stakeholders involved and the funding supporting the sector is also needed. Assembling all of this information into a sectoral overview is the final step to inform action. In addition to describing in this brief what is involved in sectoral assessment, we outline how the assessment can be built on to more effectively supply tree planting material.