The business was founded as Oishi Restaurant in 2000 by Tan Passakornnatee, and soon branched out to produce green tea drinks, quickly becoming the market leader in Thailand.

The company was listed on the Stock Exchange of Thailand as Oishi Group in 2004, and was acquired by the Thai beverage giant ThaiBev in 2008.

[4][5] The campaigns led to significant expenses cutting into Oishi's profits in 2013, and the company scaled back to refocus on cultivating its brand image and expanding its restaurant business.

[2][6] The ready-to-drink tea market stagnated and shrank during the latter half of the decade, due in part to health concerns and newly imposed taxes over sugar-sweetened beverages.

[7][8] Oishi began distribution of its drinks in Malaysia and other ASEAN countries in 2013 via Singapore-based Fraser and Neave, which ThaiBev had recently acquired.

[12] Oishi launched ready-to-cook and ready-to-eat food product lines in 2018, although as of 2020 they still comprised only a small fraction of the company's revenue.