Marilao ([mɐɾiˈlaʊ]), officially the Municipality of Marilao (Tagalog: Bayan ng Marilao), is a municipality in the province of Bulacan, Philippines. According to the 2020 census, it has a population of 254,453 people.

Marilao is derived from the Tagalog word "marilaw", which translates to yellowish, with its root word "rilaw" is linked to "dilaw," the Tagalog term for yellow. This is in reference to a yellow plant that grew abundantly in the area.

Long before the establishment as an independent town, Marilao traces its origin to a barrio of its neighboring town Meycauayan. Franciscan missionaries from Meycauayan built a visita (chapel) dedicated to Saint Michael the Archangel therein.

Marilao, just like Pangil, a town in Laguna, Philippines, was under the stewardship of the Franciscan order.

On April 21, 1796, the Barrio of Marilao was established as a pueblo as approved by the Alcalde Mayor of Bulacan and the Franciscan friars of Meycauayan, with the approval of Archbishop of Manila, the visita of San Miguel Arcangel became a town church where Padre Vicente de Talavera served as its parish priest. Between 1901 and 1903, it was consolidated with Meycauayan. In 1913, Marilao completely became an independent town.

Marilao is 22 kilometers (14 mi) from Manila and 23 kilometers (14 mi) from the provincial capital Malolos City.

With the continuous expansion of Metro Manila, Marilao is part of Manila's built-up area which reaches San Ildefonso on its northernmost part.

Marilao is politically subdivided into 16 barangays - as shown in the matrix below - all classified as urban. Each barangay consists of puroks and some have sitios.