Indonesia has the largest economy in Southeast Asia.

Indonesia has the largest economy in Southeast Asia (ASEAN). According to ASEAN Secretariat data, Indonesia's Gross Domestic Product (GDP) in 2017 reached US$1.01 trillion, or more than Rp 14 quadrillion, surpassing all other ASEAN countries. This figure represents 37% of the combined economy of the ten ASEAN countries, which totaled US$2.77 trillion.

Thailand had the second-largest economy in ASEAN, with a GDP of US$455 billion, followed by Singapore (US$324 billion) in third place. Brunei Darussalam had the smallest economy, reaching only US$12.2 billion.

(Databoks: Indonesia Enters the List of Countries with a GDP of US$1 Trillion)

Based on data from Indonesia's Central Bureau of Statistics (BPS), Indonesia's GDP in 2018 reached Rp 14,837 trillion, equivalent to US$1.059 trillion, with economic growth of 5.17% compared to the previous year.