Abacci Music Lessons - Music theory lessons with accompanying MIDI files.

Analysis of Masterpieces - Analysis of full-music 20th Century atonal pieces.

A-Natural Atonality - Claims that atonality is unnatural while tonality is acoustically and historically natural.

The Ancient Musical Modes - Ideas regarding the "classical modes" described by Plato and Aristotle.

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.

Auto-Transposer - Transposes all twelve major keys of chord progressions.

A Beginner's Guide to Modal Harmony - A concise explanation of the Gregorian and Renaissance modes and their development in the Common Practice era.

Bimodalism - A contemporary alternative to atonal styles of composition.

Chaos Music Paper I: Aesthetic Evaluation - Essays explaining computer music theory providing detailed analysis.

Chordwizard: How Music Works - A concise summary of important concepts in music.

Creativelab - Visual representations of music expressed in terms of color. In English, Ukrainian and Russian.

Dolmetsch: Music Theory & History Online - Offers a musical dictionary, recorder lessons, instrument information and a composers listing.

Dynamic Spectrograms of Music - Provides a type of spectrogram suitable for understanding the structure of music.

eMusicTheory.com - Java applets designed to help students of music improve their basic music reading skills.

Eric Weisstein's Treasure Trove of Music - A reference resource on music theory, covering in brief a vast array of topics.

Essentials of Music Theory - Summarizes entry-level music theory through advanced topics. Includes beginners' drills.

The Fugue - An outline of the fundamentals of a fugue based on Hugo Norden's "Foundation Studies in Fugue."

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

Fugue Treatises, Analyses and Tools - Bibliography of fugue analysis research, writings and analysis.

Gems of Compositional Wisdom - Articles on advanced atonal and serial concepts.

Good Ear - Online ear training site.

Harmonic Bindings - A paper about the unification of Janecek's theory of imaginary tones with the two Risinger's principles of functional relations.

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.

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.

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

Modes and Scales in Indian Music - A historical look at concepts of Indian scales and modes comparing North and South Indian approaches.

Music Acoustics - The science of music. Explanations of how musical instruments work via waves and frequency modulation.

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.

Music Theory - Covers intermediate and slightly advanced topics in tonal music theory.

Music Theory for the Short Attention Span - Essential music theory knowledge, briefly explained.

Music Theory Help Site - Intermediate music theory help covering basics through beginning formal analysis and counterpoint.

Music Theory Instruction - Online instruction for all musicians beginner or advanced. Covers scales, chordal theory, progression theory, modes and foreign scales.

The Music Theory Minute - Online music theory tutorials for beginning students.

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.

Music Worksheets - Downloadable worksheets for elementary and middle school students.

The Musical Intervals Tutor - Offers interactive music intervals and self-testing.

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.

Nuottila - Online ear training fundamentals site. [Requires Java]

Pattern Thinking in Music - Offers visual aid to recognizing musical patterns occurring in melody, harmony and rhythm. Provides online demonstration; requires download.

Polytempo Music Articles - Articles by John Greschak. Includes an annotated bibliography of polytempo music.

Rhythm Exercises - Notation for drills, rudiments and etudes for practicing rhythm.

Ricci Adams' Musictheory.net - Includes introductory and intermediate music theory lessons, ear trainers, and books.

SchenkerGuide - An introduction to Schenkerian analysis for undergraduate music students. Includes background, working method, glossary and bibliography.

Schoen Musical Notation - Julius Schoens alternative to traditional musical notation, has music notation documents, reference, and discussion.

Sight-Reading Rhythmic Patterns - Rhythmic exercises with accompanying MIDI files.

Simplified Music Chord Theory - Explains scales and building chords from them.

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.

Society for Music Theory - Includes a database of journal article from the SMT Journal.

Solomon's Music Resources - Resources for composers, music theorists, and researchers of music, with sound files, papers and compositions.

Star Theory - Free preparatory syllabus in music theory and orchestration.

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.

Teoria - Includes software, books, exercises, and links.

Theory on the Web - Intermediate music theory review for college students.

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.

Tonality Guide - Fundamentals of tonality and music theory created as an online teaching tool with written and aural examples.

8-Tone Quarto-Modes Concept - Information with mp3 files, an introduction to the "diminished-major" and its applications.

VCU Music Theory Resources - Music theory and ear training resources from Virginia Commonwealth University.

Visualizing Music: A Model of Harmony - Visual model of music which geometrically describes relationships in harmony.

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.

WholeArts - Music Conservatory - Introductory dialogue for courses in music theory and composition.