The Greencards are an American progressive bluegrass band that formed in 2003 in Austin, Texas, and relocated in 2005 to Nashville, Tennessee. The band was founded by Englishman Eamon McLoughlin and Australians Kym Warner and Carol Young. The musicians originally performed in local Austin bars, and soon found increasing acclaim. They released one independent album, Movin' On, in 2003, and two albums, Weather and Water and Viridian, on the Dualtone record label. Their fourth album, Fascination, was released on Sugar Hill in 2009. Their fifth album, The Brick Album (2011), was self-produced with the direct support of their fans. Pre-production donors were recognized with their names inscribed on the "bricks" that make up the cover art.

Their debut album, Movin' On, was the recipient of local Texas awards and charted on Americana radio stations. Country Music Television named their follow-up, Weather and Water, as one of the ten best bluegrass albums of 2005, and The Greencards were invited to tour with Bob Dylan and Willie Nelson in the same year. Viridian would go on to take the number one position on Billboard magazine's Bluegrass Music Chart, making the Greencards the first international band to do so. Viridian was a critically praised album, and was nominated for Best Country Album by the Australian Recording Industry Association. The track "Mucky the Duck" from Viridian was nominated for Best Country Instrumental Performance at the 50th Grammy Awards.

The Greencards are noted for their incorporation of other genres of music within an American bluegrass sound. Often labeled as part of, and said to be representative of, the "newgrass" movement, they draw from Irish folk music, gypsy music, rock 'n' roll, folk balladry, and Latin American musical sources. The Greencards' sound has been compared to progressive American folk rock, and they have been credited with helping to expand bluegrass music.

Eamon McLoughlin left the band in December 2009, and resides in Nashville. Carl Miner, originally from Oregon, joined the group in May 2010, playing acoustic guitar. Miner won the 1999 National Flatpicking Championship at the Walnut Valley Festival, and he resides in Nashville.

The Greencards were initially composed of two Australians, Kym Warner on mandolin and Carol Young on bass, and an Englishman, Eamon McLoughlin on fiddle. Raised in South London, McLoughlin began to perform country music shows with his family on weekends, influenced by George Jones, George Strait, and Ricky Skaggs. Born to Irish parents, McLoughlin's father was head of a London-based country band. At age nine, McLoughlin moved away from piano lessons to play fiddle, and performed with his father's band. McLoughlin had earlier relocated from Brighton to Austin in 1997, after leaving the University of Sussex with a degree in Politics and American Studies. Trained in London studying Royal Schools of Music Grades before emigrating, McLoughlin also toured with the Asylum Street Spankers, Austin Lounge Lizards, Bruce Robison and Ray Wylie Hubbard after arriving in the United States.

Prior to the founding of The Greencards, Young won the Australian Independent Country Artist of the Year award in 2000, and had recorded two No. 1 Australian-charted country music singles. Young was a singer in Outback country bands and acts, including Gina Jeffreys. Young was previously nominated as "Best Female Vocalist" by the Country Music Association of Australia, and won the Australian independent country artist of the year award in 2000 due in part to her No. 1 singles "True Blue Fool" and "Part of the Past".

Warner was an aspiring bluegrass musician (which was unusual in Australia) after learning of the music from his father, an early Australian bluegrass pioneer. The winner of the Australian National Bluegrass Mandolin Championship for four consecutive years, Warner had toured with country music artists including Gina Jeffreys, and with Young in Kasey Chambers's band. Young and Warner knew each other previously, and according to Warner, had been drawn to bluegrass and American roots music through an appreciation of George Jones and Merle Haggard. Warner and Young made the decision to emigrate to America to pursue musical careers in that country, after they met. Young and Warner later lived together in Sydney while trying to find work in the moribund Australian bluegrass scene. After leaving Australia, they spent time in West Texas before relocating to Austin.

On an early trip the pair took to Austin, Warner and Young met McLoughlin at a recording session. Warner was producing an album for the recording artist Bill Atkins and found they needed a fiddle player, which led to the recruitment of McLoughlin. Initially the immigrants came to know one another through their mutual love of Monty Python, Benny Hill, and Fawlty Towers. They began to have jam sessions afterwards and there was evident chemistry between the trio, which led to their writing songs together. They named themselves The Greencards in honor of the fact that all three band members carried United States green cards. They eventually began to perform shows locally in Austin to finance the recording of what would become their debut album, 2003's Movin' On. In the process, they became one of the most popular musical groups in Austin. Representative of an emerging "newgrass" movement, the Greencards' acoustic sound was said to incorporate eclectic influences from Irish traditional, Romani gypsy, and Latin American musical sources.