Ragnheiður Gröndal or Ragga Gröndal (born 1984) is an Icelandic singer.
She was described as Iceland's best-selling artist in 2006, and was named Icelandic Singer of the Year that same year.
In 2007, she was a finalist in Söngvakeppni Sjónvarpsins; a competition looking for an artist to represent Iceland at the 2008 Eurovision Song Contest in Belgrade.
She has collaborated with other Icelandic musicians, including the band, Ske, and Haukur Gröndal.