Mariko Oi (大井 真理子, Ōi Mariko, born 1981) is a Japanese bilingual reporter and journalist based in Singapore who has worked for the BBC since 2006, when she became the network's first Japanese reporter. As of 2021, she is the Asia Business correspondent. She began her career with brief stints as an intern at Reuters in New York and an Asia Pacific producer for Bloomberg Television stationed from Tokyo. She moved to Singapore in 2006 when she joined the BBC.