
Front: King Bhumibol Adulyadej (Rama IX) in dress uniform, heavy with braid and orders, filling the right half. To the left, the issuer line รัฐบาลไทย — the Government of Thailand — the legal tender clause beneath it, and the value spelled out in Thai as ห้าสิบบาท. Behind the text a great sunburst radiates from the crowned royal cypher; the Garuda sits top left, and a serial in Thai numerals runs across the top with the Western serial low on the right. A clear window carrying an embossed 50 is set into the right margin.
Back: King Mongkut (Rama IV) seated in a frock coat, sword at his side, at a draped table bearing a large brass telescope, with a second tripod-mounted instrument and a celestial globe alongside — the king remembered for predicting the 1868 eclipse and honoured as the father of Thai science. His reign dates are printed above in Thai numerals. At the right, the vast bell of the Phra Pathom Chedi at Nakhon Pathom; big outlined 50s, Thai and Western, stack down the left.
The fifteenth series 50 baht, and Thailand's polymer experiment: introduced in 1997 and kept in issue until a paper note of the same design took over in 2004. The design was retired with the sixteenth series in 2012, and the denomination now carries King Vajiralongkorn's portrait. Older notes remain legal tender.