Teoria
Includes software, books, exercises, and links.
http://www.teoria.com/

The Fugue
An outline of the fundamentals of a fugue based on Hugo Norden's "Foundation Studies in Fugue."
http://musik.freepage.de/cpb7079/inhalt.html

Ricci Adams' Musictheory.net
Includes introductory and intermediate music theory lessons, ear trainers, and books.
http://www.musictheory.net/

Star Theory
Free preparatory syllabus in music theory and orchestration.
http://www.musicarrangers.com/star-theory/

Chordwizard: How Music Works
A concise summary of important concepts in music.
http://www.chordwizard.com/theory.html

Bimodalism
A contemporary alternative to atonal styles of composition.
http://www.ubieta.com/bimodalism/

WholeArts - Music Conservatory
Introductory dialogue for courses in music theory and composition.
http://www.wholarts.com/music/ed/intro.htm

Harmony.org.uk
By Tom Sutcliffe. Aims to help students of music theory understand the role of chord progressions in musical structures. Site includes animated demos.
http://www.harmony.org.uk/

Society for Music Theory
Includes a database of journal article from the SMT Journal.
http://www.societymusictheory.org/

Rhythm Exercises
Notation for drills, rudiments and etudes for practicing rhythm.
http://www.izap.com/~pinnacle/rhythms/

Harmonic Bindings
A paper about the unification of Janecek's theory of imaginary tones with the two Risinger's principles of functional relations.
http://www.sweb.cz/vladimir_ladma/english/music/articles/ifsa97.htm

The Basics of Reading Music
Online tutorial by Kevin Meixner.
http://www.notationmachine.com/how_to_read_sheetmusic/readingmusic.htm

Gems of Compositional Wisdom
Articles on advanced atonal and serial concepts.
http://www.cosmoedu.net/DoctorFields/

Technical Committee on Musical Acoustics
A group within the Acoustical Society of America, that concerns itself with the application of science and technology to the field of music. Contains members, a list of papers, acousticians and links.
http://www.public.coe.edu/~jcotting/tcmu/

SchenkerGuide
An introduction to Schenkerian analysis for undergraduate music students. Includes background, working method, glossary and bibliography.
http://www.schenkerguide.com/

Dolmetsch: Music Theory & History Online
Offers a musical dictionary, recorder lessons, instrument information and a composers listing.
http://www.dolmetsch.com/theoryintro.htm

Auto-Transposer
Transposes all twelve major keys of chord progressions.
http://www.autotransposer.com/

Dynamic Spectrograms of Music
Provides a type of spectrogram suitable for understanding the structure of music.
http://nastechservices.com/Spectrograms.html

Musica Theoria
Offers explanation of chords, scales, harmony, tuning systems, counterpoint. Also provides links to ear training sites, news groups and history.
http://mywebpage.netscape.com/zentaoguy/

Pattern Thinking in Music
Offers visual aid to recognizing musical patterns occurring in melody, harmony and rhythm. Provides online demonstration; requires download.
http://www.seepatts.com/

Polytempo Music Articles
Articles by John Greschak. Includes an annotated bibliography of polytempo music.
http://www.greschak.com/polytempo/

Skytopia: Music and Art Aesthetics
Author's overview of how every piece of music, every sound, and every picture can be rated on its own merits outside (as well as inside) human opinion.
http://www.skytopia.com/project/rating.html

The Ancient Musical Modes
Ideas regarding the "classical modes" described by Plato and Aristotle.
http://www.pathguy.com/modes.htm

The Method Behind the Music
A resource for music theory, music history, the physics of musical sound, and conducting.
http://www.numbera.com/musictheory/

The Musical Intervals Tutor
Offers interactive music intervals and self-testing.
http://www.musicalintervalstutor.com/

Visualizing Music: A Model of Harmony
Visual model of music which geometrically describes relationships in harmony.
http://www.geocities.com/yaaarrrgg/music/

What is Music - Solving a Scientific Mystery
Provide information on the book by Philip Dorrell which explains a new scientific theory about music: the super-stimulus theory.
http://whatismusic.info/

Music Theory Instruction
Online instruction for all musicians beginner or advanced. Covers scales, chordal theory, progression theory, modes and foreign scales.
http://www.angelfire.com/music5/theory/

Schoen Musical Notation
Julius Schoens alternative to traditional musical notation, has music notation documents, reference, and discussion.
http://www.illuschoen.net/sn/sn.htm

Solomon's Music Resources
Resources for composers, music theorists, and researchers of music, with sound files, papers and compositions.
http://solomonsmusic.net/

eMusicTheory.com
Java applets designed to help students of music improve their basic music reading skills.
http://www.emusictheory.com/

8-Tone Quarto-Modes Concept
Information with mp3 files, an introduction to the "diminished-major" and its applications.
http://www.jazcraft.net/8tone.html

Simplified Music Chord Theory
Explains scales and building chords from them.
http://www.rpsoft2000.com/rps_chordtheory.htm

Chaos Music Paper I: Aesthetic Evaluation
Essays explaining computer music theory providing detailed analysis.
http://www.freewebs.com/gustavsphinx/

Music Theory for the Short Attention Span
Essential music theory knowledge, briefly explained.
http://www.folkblues.com/theory/

Tonality Guide
Fundamentals of tonality and music theory created as an online teaching tool with written and aural examples.
http://www.tonalityguide.com/

Fugue No. 17: A-Flat Major
Introduction to the essential concepts of Schenkerian analysis applied to the Ab Major fugue of Bach's Well-Tempered Clavier, Book I
http://jan.ucc.nau.edu/~tas3/wtc/i17.html

A Beginner's Guide to Modal Harmony
A concise explanation of the Gregorian and Renaissance modes and their development in the Common Practice era.
http://www.standingstones.com/modeharm.html

Music Acoustics
The science of music. Explanations of how musical instruments work via waves and frequency modulation.
http://www.phys.unsw.edu.au/music/

Analysis of Masterpieces
Analysis of full-music 20th Century atonal pieces.
http://www.geocities.jp/musikanalyse/eng/text/textE.html

The Music Theory Minute
Online music theory tutorials for beginning students.
http://www.musictheoryminute.com/

Fugue Treatises, Analyses and Tools
Bibliography of fugue analysis research, writings and analysis.
http://www.kunstderfuge.com/theory.htm

A-Natural Atonality
Claims that atonality is unnatural while tonality is acoustically and historically natural.
http://www.greenwych.ca/atonal.htm

Modes and Scales in Indian Music
A historical look at concepts of Indian scales and modes comparing North and South Indian approaches.
http://chandrakantha.com/articles/scales.html

Creativelab
Visual representations of music expressed in terms of color. In English, Ukrainian and Russian.
http://creativelab.kiev.ua/

Abacci Music Lessons
Music theory lessons with accompanying MIDI files.
http://www.abacci.com/music/lessons/default.asp

Music Theory
Covers intermediate and slightly advanced topics in tonal music theory.
http://www.fortunecity.com/tinpan/lennon/23/theory.html

Essentials of Music Theory
Summarizes entry-level music theory through advanced topics. Includes beginners' drills.
http://musictheory.redzeppelin.org/

VCU Music Theory Resources
Music theory and ear training resources from Virginia Commonwealth University.
http://www.people.vcu.edu/~bhammel/theory/resources/index.html

Interval and Chord Ear-Training
This site drills ear-training (aural skills), focusing on the aural recognition of musical sounds, including intervals and chords.
http://www.auralskills.com/

Music Worksheets
Downloadable worksheets for elementary and middle school students.
http://www.musicatschool.co.uk/worksheets.htm

Theory on the Web
Intermediate music theory review for college students.
http://www.smu.edu/totw/toc.htm

Music Theory Help Site
Intermediate music theory help covering basics through beginning formal analysis and counterpoint.
http://www.wmich.edu/mus-history/TheoryHelp/TheoryHelp.html

Sight-Reading Rhythmic Patterns
Rhythmic exercises with accompanying MIDI files.
http://www.rhythm-patterns.narod.ru/

Eric Weisstein's Treasure Trove of Music
A reference resource on music theory, covering in brief a vast array of topics.
http://www.ericweisstein.com/encyclopedias/music/

The Tonal Centre
Interactive site for music composers and theorists which explains and demonstrates some of the key concepts of tonality; including chords, scales, cadences, and modulation.
http://www.tonalcentre.org/

Nuottila
Online ear training fundamentals site. [Requires Java]
http://www.nuottila.info/2007/

The Musical Octave
Thomas Váczy Hightower's study of musical scales. Discuses the meta-physical properties of music and the creation of musical scales from an acoustic and mathematical perspective.
http://home22.inet.tele.dk/hightower/

Music Theory Society of New York State
Provides a forum for the exchange of information and to promote music theory as a scholarly and pedagogical discipline. Site also contains membership and scholarship information as well as open calls for papers.
http://www.ithaca.edu/music/mtsnys/

Music Theory
A guide to music theory that including chords, scales, music notation and other music theory topics. Has weblog format; includes links as well.
http://www.musictheoryblog.blogspot.com

Interactive Circle of Fifths
A free music theory tool designed to help musicians interpret chord progressions, easily transpose music to a different key, compose new music, and understand key signatures, scales, and modes.
http://randscullard.com/CircleOfFifths/

Atonal Set Calculator
Interactive atonal set calculator for pitch class sets and twelve-tone rows. Enter one or two sets and find normal order, prime form, Forte number, interval vector, and symmetry.
http://ericandchar.com/atonal/