This inventory includes metadata on various quantitative and qualitative sources of information on Syrian migration to Europe in 2011-21 that can be used for agent-based modelling purposes, with each source accompanied by data quality assessment. The files are available in a TSV and MS Excel format. The judgement-based quality ratings provided are specific to the requirements of agent-based modelling, as detailed in the background paper. A queryable version of the inventory is available on the website of the project Bayesian Agent-Based Population Studies (BAPS), funded by the European Research Council (725232): https://baps-project.eu/inventory/data_inventory. The methodology behind assembling this dataset and assessing the individual data sources according to pre-defined quality criteria is detailed in: Nurse S and Bijak J (2022) Building a Knowledge Base for the Model. In: J Bijak et al., Towards Bayesian Model-Based Demography. Agency, Complexity and Uncertainty in Migration Studies. Methodos Series, vol 17. Springer, Cham. https://doi.org/10.1007/978-3-030-83039-7_4