BACKGROUND: The Paris Declaration on Aid Effectiveness, which provides an international agreement on how to deliver aid, has recently been reviewed by the Organization for Economic Co-operation and Development (OECD). Health sector aid effectiveness is important, given the volume of financial aid and the number of mechanisms through which health assistance is provided. Recognizing this, the international community created the International Health Partnership (IHP+), to apply the Paris Declaration to the health sector. This paper, which presents findings from an independent monitoring process (IHP+Results), makes a valuable contribution to the literature in the context of the recent 4th High Level Forum on Aid Effectiveness in Busan, Korea. METHODS: IHP+Results monitored commitments made under the IHP + using an agreed framework with twelve measures for IHP + Development Partners and ten for IHP + recipient country governments. Data were collected through self-administered survey tools. IHP+Results analyzed these data, using transparent criteria, to produce Scorecards as a means to highlight progress against commitments and thereby strengthen mutual accountability amongst IHP + signatories. RESULTS: There have been incremental improvements in the strengthening of national planning processes and principles around mutual accountability. There has also been progress in Development Partners aligning their support with national budgets. But there is a lack of progress in the use of countries' financial management and procurement systems, and in the integration of duplicative performance reporting frameworks and information systems. DISCUSSION AND CONCLUSIONS: External, independent monitoring is potentially useful for strengthening accountability in health sector aid. While progress in strengthening country ownership, harmonisation and alignment seems evident, there are ongoing challenges. In spite of some useful findings, there are limitations with IHP + monitoring that need to be addressed. This is not surprising given the challenge of rigorously monitoring Development Partners across multiple recipient countries within complex global systems. The findings presented here suggest that the health sector is ahead of the game--in terms of having an established mechanism to promote alignment and harmonisation, and a relatively advanced monitoring framework and methods. But to capitalise on this, IHP + signatories should: a) reaffirm their commitments to the IHP+; b) actively embrace and participate in monitoring and evaluation processes; and c) strengthen in-country capacity notably amongst civil society organizations.