Music Online: Classical Scores Library. More than 53,000 titles and 1.3 million printable pages of important scores in classical music, ranging from the Middle Ages to the 21st century. Approximately 4,600 composers are included, from Mozart and Tchaikovsky to contemporary artists, including Kaija Saariaho, Peter Maxwell-Davies, and John Tavener.
IMSLP - Petrucci Music Library. Roughly half a million items, including scores or parts of 165,000 works. IMSLP stands for "International Music Score Library Project." The collection is named for Ottaviano Petrucci, printer in 1501 of the first book of polyphonic music set in movable type.
Recent Researches in Music Online. The series comprises two kinds of editions: those that span the history of Western music, and those with ties to specific cultural milieus. Most editions are devoted to works by a single composer or in a single genre.
Project Gutenberg Sheet Music Project. Digitized public-domain sheet music, emphasis on chamber works.
Public Domain Sherpa. A guide to finding and using free sheet music.
Free-scores.com. c.67,000 items. Free downloads of scores in many genres, links to vendors of scores and instruments, and links to other sites offering free sheet music downloads.
The Mutopia Project. c.1900 items. Free scores based on editions in the public domain. Works by Bach, Beethoven, Chopin, Handel, Mozart, and others. Volunteers typeset the music and create the digital files.
Sheet Music Online. Free public domain sheet music downloads.
Musopen. The site's stated goal is to be the largest online repository of free musical scores in the public domain.
Web Library of Seventeenth-Century Music. Provided by the Society for Seventeenth-Century Music: 17th-century works in modern editions for scholars, performers, and students.
Josquin Research Project. Polyphonic music from the period c.1420-1520.
Juilliard Manuscript Collection. Manuscripts, sketches, engravers' proofs and first editions, including an engraver’s proof of Beethoven’s ninth symphony with annotations by the composer, the manuscript of Beethoven’s Grosse Fuge in his arrangement for piano 4 hands, and the last scene of Mozart’s Marriage of Figaro, together with select manuscripts from the Juilliard Library’s Special Collections, including scores in the Artur Rubinstein Music Collection.
University of Washington Music Library Digital Scores Collection. Scores dating from the 17th through 19th centuries, most of them 17th- and 18th-century operas, opera excerpts, and other vocal music.
African-American Sheet Music (Brown University). Music by, and relating to, African-Americans from the 1820s to the present.
Loeb Music Library, Harvard University. Digital collection of scores and libretti, selected for their rare or unique natures and their popularity as objects of research and teaching.
Digital Image Archive of Medieval Music (University of Oxford and Royal Holloway, University of London). Images and metadata for thousands of medieval manuscripts.
Early Music Online (Royal Holloway, University of London, the British Library and JISC). Digitized images of some of the world's oldest surviving volumes of printed music.
University of North Texas: Virtual Music Rare Book Room. A digital collection particularly strong in eighteenth-century French opera.
Indiana University VARIATIONS (scores collection). Experimental prototypes of ways in which scores and recording liner notes might be used in conjunction with sound recordings available online through VARIATIONS.
The Morgan Library & Museum Music Manuscripts Online. High-quality images of music manuscripts owned by the Morgan Library & Museum. Works by Bach, Beethoven, Brahms, Chopin, Fauré, Debussy, Haydn, Liszt, Mahler, Massenet, Mendelssohn, Mozart, Puccini, Schubert, and Schumann, others.
Library of Congress Music Treasures Consortium. Primary source manuscripts, early printed editions of notated music, early treatises on music, and correspondence of prominent composers. See also the scores available in Library of Congress Collections with Manuscripts/Mixed Materials.
Munich DigitiZation Center (Bavarian State Library). Free access to hundreds of scores by Beethoven, Schumann, Distler, Mendelssohn, Michael Haydn, Rheinberger, others, including complete works sets of Liszt, Handel, and others.
Beethoven-Haus Bonn. Text, image and audio of Beethoven scores.
Brahms-Institut an der Musikhochschule Lübeck. c.40,000 digitized scores, letters, photographs.
Chopin’s Editions Online. c.400 first and early editions in the University of Chicago Library.
Bach Digital Database (Leipzig Bach Archive). High-resolution scans of nearly all of J. S. Bach’s works.
Schubert-online. Free access to images of c.500 manuscripts and c.600 early editions of works by Franz Schubert, together with selected autograph letters and biographical documents.
Schumann autographs (Bonn University Library). Autograph scores and letters of Clara and Robert Schumann.
Classical String Quartets (Duke University Libraries). Collections of string quartets dating from c.1770-1840, representing composers whose works are seldom found in modern editions.
Contemporary Music Score Collection (UCLA Music Library). Open-access scores from the Contemporary Score Edition series, the first open-access edition of new music published by a library.
Archive of Seventeenth-Century Italian Madrigals and Arias (University of Birmingham). Critical editions, with introductions and translations.
New York Philharmonic Digital Archives. Includes marked conducting scores and parts, business documents, printed programs, photographs.
Free Jazz Chord Charts That You Can Transpose — c.1300 chord charts of jazz standards that can be transposed to any key.
Jean-Luc Barbier Quartet: Les standards du Jazz — Website of Jean-Luc Barbier, saxophonist and jazz flutist. Contains the archives of his quartet from 1975 to1986.
eJazzlines — A large selection of jazz arrangements, including combo charts, jazz studio orchestra arrangements, vocals and instrumentals. Difficulty levels of easy to professional, classics from the dixieland and swing eras to jazz arrangements of current hits. Updated daily.
The Fake Book Library — A collection of musical lead sheets intended to help a performer quickly learn new songs.
ChoralWiki : Choral Public Domain Library — CDPL was Founded in 1998, ported to ChoralWiki in 2005, and incorporated in 2010 as a tax-exempt charitable organization. Free choral/vocal scores, texts, translations, and other useful information.
Art Song Central — Free sheet music, chiefly classical, for singers and voice teachers.
Sheet Music Consortium — Tools and services that promote access to and use of online sheet music collections by scholars, students, and the general public.
Chatfield Brass Band & Music Lending Library — The library is a member of the Southeast Minnesota Library System and lends music to bands and musicians from all over the world. Borrowers are charged a small handling fee to cover expenses. The library has collected and cataloged more than 30,000 pieces, many of which are no longer in print.The music collection not only includes band music (the largest portion), but also orchestra, dance band, sheet music, and numerous other categories.
BandMusic PDF Library — BandMusic PDF Library preserves and shares band music from the Golden Age of the American Town Band. If you are looking for public domain music to play with a school band, community band, or other group, you will find it here — marches, waltzes, rags, theater music, cornet solos, trombone features, and more.