Willie Mae "Big Mama" Thornton (December 11, 1926 – July 25, 1984), was an American singer and songwriter of blues and R&B.

The Encyclopedia of Pop, Rock and Soul described Thornton by saying: "Her booming voice, sometimes 200-pound frame, and exuberant stage manner had audiences stomping their feet and shouting encouragement in R&B theaters from coast to coast from the early 1950s on". Thornton's strong and important vocal style and her confidence on stage made her a huge influence on early blues and rock and roll, even though she rarely received proper credit and compensation for her work.

Thornton was the first to record Leiber and Stoller's "Hound Dog", in 1952, which was written for her. It became Thornton's biggest hit, selling over 500,000 copies and staying seven weeks at No. 1 on the Billboard R&B chart in 1953. According to New York University music professor Maureen Mahon, "the song is seen as an important beginning of rock-and-roll, especially in its use of the guitar as the key instrument".

Thornton's other recordings include her song "Ball and Chain", made famous in the late 1960s by Janis Joplin. Though later recordings of her songs by other artists sold millions of copies, she was denied royalties by not holding the publishing copyrights to her creativity. Thornton died in July 1984 of a heart attack and liver disorders, penniless in a boarding house in Los Angeles, California. Thornton was posthumously inducted into the Rock and Roll Hall of Fame in 2024 under the Musical Influence category.

Thornton was born on December 11, 1926, the sixth of George and Mattie (née Haynes) Thornton's seven children. While Thornton's birth certificate states that she was born in Ariton, Alabama, in an interview with Arhoolie Records producer Chris Strachwitz, she claimed Montgomery, Alabama, as her birthplace. She was introduced to music in a Baptist church, where her father was a minister and her mother a singer. Thornton said: "I used to go to church a lot, but I didn't do too much singing in church." She was later introduced to gospel music by the church and this heavily influenced her artistic side. Thornton's mother fell gravely ill from tuberculosis. Only 13 years of age, Thornton cared for her mother until her death in the Montgomery Tuberculosis Sanatorium in 1939. At the time Thornton was in the third grade. After losing her mother, she was unable to continue to attend school. Thornton left school and got a job washing and cleaning spittoons in a local tavern.

Thornton's talent was self-taught. She said: "My singing comes from my experience... My own experience. I never had no one teach me nothin'. I never went to school for music or nothin'. I taught myself to sing and to blow harmonica and even to play drums by watchin' other people! I can't read music, but I know what I'm singing! I don't sing like nobody but myself." When Thornton was 8 years old, she taught herself to play the harmonica by watching her older brother, Calliope "Harp" Thornton. Observing the rhythm-and-blues singers Bessie Smith and Memphis Minnie, whom she deeply admired, helped develop her singing talent. "I just started hearing the blues of Bessie Smith, well I was a kid myself, you know. I was a young type of youngster always running around the house humming the blues and my daddy wanted to get me with the razor strap, but I hit the door." Thornton explained her early love of the blues, saying: "My father was a minister. He's a Baptist preacher, and my mother she was very religious. And me, I don't know what I am, I'm -- well, [I] was just born with the blues... I really got the blues, you know, in '39 when I lost my mother, and then I said, 'Well, I don't know what to do'. I said, 'Well, I think I want to sing the blues'. So I said, well, [at] that time, I was listening to Big Maceo, his "Worried Life Blues" and I said 'I think I want to sing that', and I did. That was a beautiful number. Yeah."

Thornton's talent was discovered in 1940 when she was 14 years old. Diamond Teeth Mary, the half-sister of one of her early idols Bessie Smith, encouraged her to enter a talent contest after having heard Thornton singing while working a side-job on a garbage truck. Thornton described the audition during a 1970 Studs Terkel radio interview, saying: "A show came through in the first of the 1940s and they called it 'Sammy Green's Hot Harlem Revue' as I mentioned earlier. They didn't have a singer, and so I asked him, I said, 'Give me an audition, let me sing'. I said, 'I've been singing all the little talent shows around here'. He said, 'Oh, little 'ole girl, you can't sing'. I said, 'Will you give me a try?' He said, 'Yeah, well, when the show start, say we gonna give a little audition for singers, 'cause I'm looking for a singer'. And so he give auditions. So I was there, he wrote my name down, and several people they sung, and then he said, 'Well, I, I want to see what you can do'. So I got up there, I had an old pair of jeans, one leg rolled up, I got up and I started singing one of Louis Jordan's song called "G.I. Jive", and I sung that song, and I sang this blues by Big Maceo, "Worried Life Blues" and he hired me. Out of 25 people, I was the 26th but then he hired me."

Thornton left home at age 14, traveling with Green's show in Alabama and Georgia. Thornton described the revue as "a stage show, like, playing in theaters... dancers, chorus girls, comedians, singers". Originally hired as a dancer, singer, and comedienne, Thornton quickly became known as the "New Bessie Smith" for her vocal talent. Thornton left Green's show in 1948 over a money dispute, about which she said: "I traveled with them for quite a few years, and I went to Houston, Texas in '48. We played there and then we left. As a matter of fact, I quit the show in '48... They owed me a little, quite a bit of money and they wouldn't pay it, and I just got tired."