Luisa Tetrazzini (29 June 1871 – 28 April 1940) was an Italian coloratura soprano of great international fame. Tetrazzini "had a scintillating voice with a brilliant timbre and a range and agility well beyond the norm...". She enjoyed a highly successful operatic and concert career in Europe and America from the 1890s through to the 1920s. Her voice lives on in recordings made from 1904–1920. She wrote a memoir, My Life of Song, in 1921 and a treatise, How to Sing, in 1923. After retirement, she taught voice in her homes in Milan and Rome until her death.

Tetrazzini was born on 29 June 1871, in Florence, Italy. Her father was a tailor and she had two sisters and two brothers. Reportedly, she began singing at the age of three. Luisa herself recalled singing early on as a child and reminisced that her father was the first person to ever compare her to the famous bel canto soprano, Adelina Patti. Luisa first studied singing with her oldest sister, Eva Tetrazzini (1862–1938)(it). Eva was also a prima donna soprano who made a name for herself internationally. While doing chores, Luisa was known to practice entire acts of operatic roles and to sing every voice part. She began studies at the Istituto Musicale between the age of ten and thirteen with Professor Ceccherini. She married Giuseppe Santino Alberto Scalaberni on 14 October 1889.

Through a stroke of luck, Tetrazzini stepped in for an ailing prima donna and made her operatic debut in Florence on 21 October 1890, as Inez in Meyerbeer's L'Africaine at age nineteen. She reminisces that after her debut, “The pavements from the theatre to my home were lined, even at that late hour, with large numbers of people, all of whom seemed to be shouting congratulations to me.” Next, she sang Inez in Rome on 26 December 1890, for the King and Queen of Italy. She was then invited by the Queen to sing the Liebestod from Tristan und Isolde, as it was the Queen’s favorite opera. The first part of her career was spent mainly in the Italian provincial theaters and then touring in South America. She travelled with Pietro Cesare, who became her lover of nearly 14 years, to Buenos Aires where she was offered £280 per month to sing. While in Buenos Aires, her husband, Alberto, followed her to attempt to return her to Florence. She refused to reconcile. He left for Florence without her in October, and she made her debut a few days later as Annetta in Crispino e la comare. When Alberto died on 4 June 1905, they were still separated.

Tetrazzini first sang Lucia di Lammermoor in Buenos Aires on 21 November 1892. It was her favorite opera, as well as that of Argentinian President Luis Sáenz Peña. He was her avid fan. By the time of her fourth season in Buenos Aires, she was engaged to receive £5,500 per month. Along with performing in Argentina, she toured South America. She continued to sing there until 1895.

She returned to sing in Europe in 1896. Next she debuted in Saint Petersburg with Mattia Battistini in Un ballo in maschera on 31 December 1896. After her first season in St. Petersburg ended in 1897, she finished the year performing in Madrid, Milan, Turin and Odessa. In 1898, she sang in Odessa and Bologna before returning to perform in various South American countries. The winter season of 1899 brought Tetrazzini back to St. Petersburg. This is where she first performed with Enrico Caruso, who sang Edgardo to her Lucia in Lucia di Lammermoor on 22 February 1899. Her 1890s' repertory consisted primarily of lyric-coloratura parts such as Violetta, Philine, Oscar, Gilda, and Lucia.

From 1899 to 1903, she sang in Italy, Germany, Poland, and Russia. Her Mexican debut as Lucia came on 22 October 1903. A little over a year later, her performance of Lucia on 8 December 1904, was fortuitous. William H. ‘Doc’ Leahy, impresario of San Francisco's Tivoli Theater, was in attendance. He was in Mexico visiting his friend, Ettore Patrizi, who was conducting Tetrazzini at the time. Leahy invited her to come to San Francisco. She made her American debut at the Tivoli in San Francisco as Gilda in Rigoletto on 11 January 1905.

Due to Dame Nellie Melba's absence, an opening came for Tetrazzini at the esteemed Covent Garden in London. Although she had established a career throughout South America and much of Europe, she was practically unknown to English audiences. Tetrazzini's debut at Covent Garden as Violetta in La traviata on 2 November 1907 was critically acclaimed and "caused a sensation..." She garnered twenty curtain calls. E.A. Baugham in the Daily News wrote, "The quality of tone produced by Tetrazzini ravished the sense. It is soft and golden and yet has none of the impersonal and chilling perfection of the ordinary light soprano...I have never seen the pathos of Verdi’s heroine realized with such grip and sincerity... I do not think I am exaggerating when I say that Mme Tetrazzini has the voice of the century and stands out from even the great Italian singers we know..." Additional reviews were similarly complimentary of Tetrazzini’s abilities, even comparing her to the famous Adelina Patti, the premiere soprano of an earlier generation. Tetrazzini idolized Patti greatly. She remarks that Patti saw her performance and invited her to a lunch in which she confirmed the press’s clamoring that Tetrazzini would continue her legacy. Tetrazzini and Patti became great friends, and were frequent correspondents until Patti's death. Patti made it a point to attend and loudly applaud the younger soprano's performances. Tetrazzini remarks about a letter from Patti about one of her performances that she prized it as her greatest treasure saying, "Praise from a mixed audience is very gratifying after one has given it of her best. But, praise, and such praise, from Patti is far more than the passing pleasure of a public ovation."

From this point on, Tetrazzini was an international operatic superstar, commanding the highest fees and selling out opera houses and concert halls wherever she performed. In 1904, the Metropolitan Opera's general manager, Heinrich Conried, had tried to engage Tetrazzini with a contract that committed her to singing with the Met for three years starting in November 1905. This contract never became binding as Conried failed to give her bank the guarantee deposit. In 1908, Tetrazzini finally appeared in New York City, not at the Metropolitan, but at Oscar Hammerstein's Manhattan Opera Company, again as Violetta with great success. She remained loyal to Hammerstein and appeared at the Met for only one season, in 1911-12 (giving just eight performances, in the roles of Lucia, Violetta, and Gilda). From 1911 to 1914 she sang with the Boston Opera Company and Chicago Grand Opera Company.