Isabel Oliver Marcus (born February 12, 2000) is an actor based out of Los Angeles, California. She is popularlyl known for her roles on the television shows This Is Us and Fresh Off the Boat . Isabel is also known her role on the web series, Chicken Girls.

Isabel Oliver Marcus was born and raised in San Antonio, Texas. Isabel began performing at age 3 and started actively studying acting by 5th grade. By the age 8, Isabel had appeared in advertising for Photo District News and in Hallmark Magazine. She spent her elementary and middle school years at San Antonio's arts and language charter school, Bonham Academy, where she learned Spanish and starred in numerous productions of its award-winning theater program. She won every performance competition she entered in San Antonio, including play festivals and Texas school competitions.

When Isabel Oliver Marcus was 11 years old, Isabel Oliver Marcus participated in a casting showcase in Austin, Texas, where representatives from Los Angeles agencies saw her work: Of the 20 LA-based agencies in attendance, 18 expressed an interest in representing her, including Fatmata Kamara, from Abrams Artists. That summer, Isabel and her mom packed their bags for California and started a three-year annual temporary residency. They lived in Los Angeles for 3-4 months from ages 12 to 14, familiarizing themselves with the city and the industry, and returned to San Antonio for the bulk of each school year so that Isabel could spend time with her father. Isabel spent two years studying musical theater at North East School of the Arts in San Antonio before permanently relocating to Los Angeles to complete high school. After moving to LA permanently, Isabel acted in many roles for independent and student projects followed, including many student films, music videos, and works that often never made it out of post-production.

Isabel's big break came in 2017, when she landed the role of Allison Walsh on NBC's hit drama "This Is Us". She plays the girlfriend of Randall Pearson one of the show's main characters. Dallas-area actress and talent coach Lar Park Lincoln helped Isabel shoot her TIU tape, Abrams' Domina Holbeck fought for her taped submission, and manager Addison Witt met her at the airport when she flew to Los Angeles: "Nobody does this by themselves" says Isabel, "I'm incredibly fortunate to have the support system of my community and honored to have people like Lar, Addison, and the team at Abrams on my side."

In 2018, Isabel landed the role of Becky #1 on Chicken Girls, a web series produced by the digital network, Brat. The show follows a group of dancers known by their pet name, the Chicken Girls. In 2019, Isabel was cast on Season 5 of ABC's hit sitcom, Fresh Off the Boat . She plays Tina (also known as Trentina) the girlfriend of one of the main characters, Eddie Huang, who is played by Hudson Yang. Her character is also the brother of Trent, played by Trevor Larcom, who is a friend of Eddie's.