- January 1: The European Union (EU) is officially established with the signing of the Maastricht Treaty.
- January 15: The terrorist group al-Qaeda carries out a bomb attack on a hotel in Nairobi, Kenya, resulting in the deaths of 12 people.
- February 28: The United States announces air strikes against Iraq in retaliation for its failure to comply with weapons inspections.
- April 10: The Good Friday Agreement is signed in Northern Ireland, bringing an end to decades of sectarian conflict known as "The Troubles."
- May 2: Malaysia's Prime Minister Mahathir Mohamad is elected as the new Secretary-General of the Organization of Islamic Cooperation (OIC).
- May 11: India carries out a series of nuclear tests in Pokhran, triggering an international outcry and escalating tensions with Pakistan.
- June 12: France hosts the 1998 FIFA World Cup, which concludes with France defeating Brazil 3-0 in the final match.
- July 17: The International Criminal Court (ICC) is established in The Hague, Netherlands, with the aim of prosecuting individuals responsible for war crimes, crimes against humanity, and genocide.
- August 7: Al-Qaeda carries out simultaneous bombings of the US embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, killing over 200 people.
- August 31: The United States retaliates for the embassy bombings by launching missile strikes against alleged al-Qaeda training camps in Afghanistan and a pharmaceutical factory in Sudan.
- September 16: The Lewinsky scandal erupts, leading to the impeachment of US President Bill Clinton by the House of Representatives on December 19.
- October 1: The Asian financial crisis, which had begun in 1997, intensifies as the IMF approves a bailout package for South Korea worth $57 billion.
- October 29: Hurricane Mitch makes landfall in Central America, particularly affecting Honduras and Nicaragua, resulting in widespread destruction and loss of life.
- December 11: Iraq agrees to the terms of a weapons inspections deal with the United Nations, following several years of tense negotiations and military standoffs.