Betty Ann Ong (February 5, 1956 – September 11, 2001) was an American Airlines flight attendant who was on board American Airlines Flight 11, the first airplane hijacked during the September 11 attacks. Ong was the first person to alert authorities to the hijackings taking place that day.

Shortly after the hijacking, Ong notified the American Airlines ground crew of the hijacking, staying on the radiophone for 23 minutes to relay vital information that led to the closing of airspace by the FAA, a first in United States history. For this, the 9/11 Commission declared Ong a hero.

Betty Ann Ong was born on February 5, 1956, in San Francisco. She was of Kaiping descent, a branch of Sze Yup Cantonese, and had two sisters, Cathie and Gloria, and a brother named Harry. She attended George Washington High School, graduating in 1974. Among her hobbies as an adult was collecting Beanie Babies.

Betty was once approached for work in modeling, but her mother disapproved of that career choice, so instead Ong would work at her parents' beef jerky factory. According to an account related by her sister Cathie Ong-Herrera in New York Post, an armed robbery at the factory illustrated Ong's steady nerves in a crisis situation. As Cathie described it, "Betty was out in front and had a gun held to her head. My mom said she never panicked. All she said was, 'Dad, we’re being robbed.'" The robbers were given the money they demanded and Cathie said of her sister, "She was never shook up."

In the early 1980s, she joined Pacific Southwest Airlines and worked within the airline's baggage claim department. Afterwards, she worked as a ticket agent with Delta Air Lines. In 1987, she became a flight attendant with American Airlines.

In 1987, Betty was driving south on U.S. Highway 101 in San Francisco when she witnessed a car roll over twice after it was hit by a speeding pickup truck. Betty ran to the car and saw that its occupant was Jo Ellen Chew, a woman she met a month prior at a bowling alley, who later described the "courage, kindness, [and] compassion" exhibited by Ong, saying, "Most people would just pass by. But to stop and run up to me? A miracle!"

Ong was engaged to Robert Landrum. At the time of her death, Ong lived in Andover, Massachusetts.

On September 11, 2001, Ong assigned herself to Flight 11, so she could return to Los Angeles and go on vacation to Hawaii with her sister. During the hijacking, she used a telephone card to call American Airlines' operations/Cary, NC reservations center, from the plane's rear galley; identified herself and alerted the supervisor that the aircraft had been hijacked. Along with fellow flight attendant Madeline Amy Sweeney, she relayed a report of the seat numbers of three hijackers. During her Airfone call, she reported that none of the crew could contact the cockpit or open its door; that passenger Daniel Lewin, and two flight attendants, Karen Martin and Barbara “Bobbi” Arestegui, had been stabbed; and that she thought someone had sprayed Mace in the business class cabin.