Why did the Indonesian government decide to approve Australian humanitarian assistance following the 2004 Aceh tsunami, and how did governmental agencies manage the assistance? This thesis unpacks the Indonesian foreign policy decision-making process during the first term of President Susilo Bambang Yudhoyono (SBY) in its efforts to address the crises emerging from both the Aceh tsunami and the intrastate conflict in Aceh. By utilising a theoretical framework derived from foreign policy decision-making theory, the thesis shows that not only power and interests, but also organisational structure and bargaining explain foreign policy making in the Indonesian context (Allison, 1969, 1971; Allison & Zelikow, 1999). The case selection is Australia, given that it had the military capability to undertake significant military-operations-other-than-war (MOOTW) in a high intensity environment such as the Aceh intrastate conflict. The case selection of Australia provides an understanding of how the Indonesian foreign policy-making process changed its approach toward Australia from the bitter relations that were a residual effect of Australians involvement in the East Timor conflict. The thesis is qualitative in nature. The proposed methodology includes an analysis of secondary sources as well as semi-structured interviews with foreign policy makers from various government agencies (vice presidential office, foreign ministry, military, parliament) as well as non-government agencies (journalists, academics) in order to understand the interests they represented and the positions they took in support of or in opposition to the Indonesian government's policy initiative. Content analysis has been undertaken on written documents such as books, journals, speeches of the President, government official statements, national regulations, regional and international policies, national and local newspapers, treaties, and transcripts of interviews. The thesis shows that the Indonesian government approved the international humanitarian assistance following the 2004 Aceh tsunami because of two significant factors. The first factor was the convergence of views within the government — including the President and his political advisers, the Ministry of Foreign Affairs, the Indonesian National Armed Forces (TNI), and the Indonesian Parliament (DPR) — who embraced greater openness toward foreign involvement in post-tsunami disaster recovery. The second factor was the way the Aceh tsunami changed the global narrative on natural disasters. Here, the Indonesian government took the lead amongst ASEAN members in shifting their perspective from a less-equipped organisation into developing agreements to incorporate humanitarian diplomacy in regional politics. The Indonesian government's approval of Australian humanitarian assistance to address the situation in the aftermath of the Aceh tsunami was motivated by a desired to maintain relations with the neighbouring country, employ assertive diplomacy, and utilise the closest foreign military available. It is also argued that the three key state agencies bargained with each other by utilising their organisational structures and functions within the Indonesian presidential system in order to provide support for or opposition to Australian humanitarian assistance following the Aceh tsunami. The Ministry of Foreign Affairs used its political, economic, protocol and consular functions, as well as public diplomacy, to bargain with the TNI and the DPR in order to resolve conflicting interests at the local, national, and international levels. The TNI utilised its non-military operations in order to obtain control over the humanitarian missions in Aceh and to collaborate with foreign military partners such as the ADF. Furthermore, it coordinated with the Foreign Ministry and the DPR to ensure that the ADF in Aceh was a purely humanitarian mission. The DPR employed its oversight functions in order to apply checks-and-balances on the Foreign Ministry and the TNI in their management of Australian humanitarian assistance.