BACKGROUND: There are an estimated 55 million internally displaced persons (IDPs) globally. IDPs commonly have worse health outcomes than host populations and other forcibly displaced populations such as refugees. Official development assistance (ODA) is a major source of the global financial response for health in low- and middle-income countries (LMICs), including for populations affected by armed conflict and forced displacement. Analysis of ODA supports efforts to improve donor accountability, transparency and the equitable use of ODA. The aim of this study is to examine international donor support and responsiveness to IDP health needs through analysis of ODA disbursements to LMICs between 2010 and 2019. METHODS: ODA disbursement data to LMICs from 2010 to 2019 were extracted from the Creditor Reporting System (CRS) database and analysed with Stata software using a combination of: (i) text searching for IDP and refugee related terms; and (ii) relevant health and humanitarian CRS purpose codes. Descriptive analysis was used to examine patterns of ODA disbursement, and nonlinear least squared regression analysis was used to examine responsiveness of ODA disbursement to recipient country IDP population size and health system capacity and health characteristics. FINDINGS: The study highlighted declining per IDP capita health ODA from USD 5.34 in 2010 to USD 3.72 in 2019 (with annual average decline of -38% from the 2010 baseline). In contrast, health ODA for refugees in LMICs increased from USD 18.55 in 2010 to USD 23.31 in 2019 (with an annual average increase of +14%). Certain health topics for IDPs received very low ODA, with only 0.44% of IDP health ODA disbursed for non-communicable diseases (including mental health). There was also weak evidence of IDP health ODA being related to recipient country IDP population size, and health system capacity and health characteristics. The paper highlights the need for increased investment by donors in IDP health ODA and to ensure that it is responsive to their health needs.