Indian Ocean Memorandum of Understanding (IOMOU) a comprehensive evaluation of the maritime safety infrastructure within the Indian Ocean region. A review conducted between August and September 1997 assessed the adequacy of maritime safety infrastructure in the Indian Ocean region, as well as requirements under the International Maritime Conventions. This review concluded that enhanced regional cooperation among countries along the Indian Ocean rim would be essential to effectively control the operation of sub-standard ships in the region.

As a result, the concept of establishing an Indian Ocean Memorandum of Understanding (IOMOU) on Port State Control was proposed. At the invitation of the Secretary-General of the International Maritime Organization (IMO) and with the generous support of the Government of India, the first preparatory meeting to develop flag and port State control capabilities in the region was held in Mumbai from 13 to 17 October 1997. Delegations from the following countries participated: Australia, Bangladesh, Djibouti, Eritrea, Ethiopia, India, Kenya, Maldives, Mauritius, Mozambique, Myanmar, Oman, Seychelles, Singapore, South Africa, Sri Lanka, Tanzania, and Yemen.

During this meeting, a draft Memorandum was prepared, which was subsequently finalized at a second preparatory and signatory meeting held in Pretoria, South Africa, from 1 to 5 June 1998. This meeting also included participation from Iran and Sudan, in addition to the earlier countries.

The finalized Memorandum was kept open for signature at the IOMOU Secretariat headquarters in Goa, India, from 5 June 1998 until 22 January 1999. The first Committee Meeting of the IOMOU was held in Goa from 20 to 22 January 1999. During this period, and at the inaugural meeting, the Memorandum was formally signed by Australia, Eritrea, India, South Africa, Sudan, and Tanzania.

In the years that followed, additional countries acceded to the Memorandum, including Mauritius, Sri Lanka, Iran, Kenya, Maldives, Oman, Yemen, France (La Réunion), Bangladesh, Comoros, Mozambique, Seychelles, Myanmar, and Madagascar. As of December 2019, a total of twenty countries had become parties to the IOMOU, which officially entered into force on 1 April 1999.