Glaiza Castro Galura-Rainey (Tagalog: [ˈglɐjsa]; born January 21, 1988), professionally known by her stage name Glaiza de Castro, is a Filipino actress and singer. She is known for playing various roles in television and mainstream, independent, and sociopolitical films. Her performances have earned her accolades, including a Luna Award and a Facine Film Festival Award, as well as several FAMAS Awards and Gawad Urian Awards nominations.

At age 13, de Castro made her first screen appearance in the series Kasangga (2001). She continued playing minor and supporting roles in the succeeding years and rose to fame after playing Eunice Aragon in the series Stairway to Heaven (2009). The following year, de Castro starred in her first titular role, Grazilda (2010), and played Binayaan in the historical epic series Amaya (2011). She gained further recognition as Heidi Fernandez in the series Temptation of Wife (2012). Her performance earned her a nomination at the Golden Screen TV Awards for Outstanding Supporting Actress in a Drama Series. In 2015, she starred alongside Rhian Ramos in the first lesbian series in the Philippines, The Rich Man's Daughter.

For her role as Pirena in the drama fantasy series Encantadia (2016), she won Best Actress at the Gawad Filipino Media People's Choice Awards and Television Actress of the Year at the PEPsters' Choice Awards. In 2018, de Castro starred in another titular role, Contessa, which earned her Best Actress wins at the EdukCircle Awards and the Alta Media Icon Awards. In 2022, she starred in the variety series Running Man Philippines with an ensemble cast. De Castro has also gained critical acclaim for her performances in the films Still Life (2007), Astig (2009), Liway (2018), and Midnight in a Perfect World (2020). As a recording artist, she has earned a gold record for her album Synthesis (2015) and was named Female Rock Artist of the Year at the PMPC Star Awards for Music.