Elijah Christian Ong Alejo (; born November 13, 2004) is a Filipino actress. She is known for both her antagonist role in Prima Donnas as Brianna and her protagonist role in Underage as Chynna.
She studied senior high school in Manila Central University, under the Science, Technology, Engineering and Mathematics (STEM) strand. She finished senior high school. She currently studies bachelor's degree in medical technology in the same school.
In April 2020, she wrote her first Wattpad novel titled "Unexpectedly In Love".
Alejo returned to the big screen in December 2025 as a cast member of Shake, Rattle & Roll Evil Origins (also known as Shake, Rattle & Roll XVII), an official entry in the 51st Metro Manila Film Festival (MMFF). Alejo joins the cast of this film, romance-comedy film "She Who Must Not Be Named" which is toplined by Francine Diaz and Seth Fedelin (FranSeth).