V/ii is a secondary dominant, a major triad or dominant seventh built on scale degree 6 that acts as the temporary dominant of ii, tonicizing the supertonic. In C major, V/ii is A major (A–C#–E) resolving to D minor, with C# serving as the chromatic secondary leading tone.
V/ii (read "five of two") is a secondary dominant chord. Instead of pointing toward the home tonic, it points toward the ii chord, treating the supertonic as a temporary tonic for a moment. That brief "pretend tonic" effect is called tonicization. To build it, take the note a perfect fifth above the root of ii (that lands you on scale degree 6) and build a major triad or dominant seventh chord on it.
Here's the giveaway in the score. The diatonic chord on scale degree 6 is vi, a minor triad. V/ii is that same chord with a raised third. In C major, vi is A–C–E, but V/ii is A–C#–E (or A7 as a dominant seventh). The C# is the secondary leading tone, and it pulls up by half step to D, the root of ii. One important catch is that V/ii only exists in major keys. In minor, the ii chord is diminished, and you can't tonicize a diminished triad because a diminished chord can never function as a tonic.
Secondary dominants live in Unit 7 of AP Music Theory, where you learn to identify, spell, and part-write chords that tonicize diatonic chords other than tonic. V/ii is one of the most common secondary dominants you'll meet, right alongside V/V, because the progression V/ii → ii → V → I rides the circle of fifths and shows up constantly in real repertoire. Recognizing it matters in every skill the exam tests. In analysis, a chromatic raised note (like C# in C major) is your clue that something is being tonicized. In harmonic dictation, that unexpected accidental signals a secondary dominant. In part writing, you have to spell the chromatic third correctly and resolve it properly. Miss the chromaticism and you'll mislabel the chord as plain vi, which is exactly the trap the exam sets.
Keep studying AP® Music Theory Unit 7
Visual cheatsheet
view galleryV/V (Unit 7)
V/V is the same idea aimed at a different target. Both are secondary dominants, but V/V tonicizes the dominant while V/ii tonicizes the supertonic. If you can spell one, you can spell the other; find the chord a fifth above the target and make it major. They also chain together beautifully, since V/ii → ii sets up V → I.
Circle of fifths (Unit 1)
The progression V/ii → ii → V → I is the circle of fifths in action. Each root falls a fifth (in C major, A → D → G → C), which is why this progression sounds so inevitable. Secondary dominants basically supercharge circle-of-fifths motion by adding a leading tone before each landing point.
Closely Related Keys (Units 7-8)
Tonicization and modulation sit on the same spectrum. V/ii makes the supertonic sound like tonic for one beat or two; modulation makes a closely related key (like ii) the actual tonic for a whole phrase. If the music keeps cadencing in the new key, you've modulated. If it snaps right back, it was just a V/ii moment.
V/ii shows up across nearly every question type. In multiple choice, you'll see a score excerpt with a chromatic accidental and have to choose the correct Roman numeral, or hear a progression in harmonic dictation where the raised tone tips you off. On the part-writing FRQs, a given Roman numeral progression can include V/ii (or V7/ii), and you have to realize it in four voices with correct spelling and resolution. The rules to nail are these. Raise the third of the chord to create the secondary leading tone, resolve that leading tone up by half step to the root of ii, resolve the chordal seventh (if there is one) down by step, and never double the chromatic leading tone. Doubling or mis-resolving that tendency tone is one of the most common ways to lose points on the voice-leading FRQs.
V/ii and vi are built on the exact same root, scale degree 6, which is why they get confused. The difference is one note. In C major, vi is A–C–E (minor) and V/ii is A–C#–E (major). The raised third changes everything about function. vi is a diatonic chord that often substitutes for tonic, while V/ii is a chromatic chord with a job to do, pulling toward ii. On the exam, if the chord on scale degree 6 has a raised third (or an added minor seventh), label it V/ii, not VI.
V/ii is a secondary dominant built on scale degree 6 that temporarily tonicizes the ii chord.
Spell it as a major triad or dominant seventh; in C major that's A–C#–E (or A7), and the chromatic note is the secondary leading tone pointing to D.
Resolve the secondary leading tone up by half step to the root of ii, resolve any chordal seventh down by step, and never double the leading tone.
V/ii does not exist in minor keys, because ii is diminished in minor and a diminished chord can't be tonicized.
The progression V/ii → ii → V → I is pure circle-of-fifths motion, which is why composers use it so often before cadences.
A chord on scale degree 6 with a raised third is V/ii, not VI; that one accidental is the difference between a diatonic and a chromatic analysis.
V/ii is a secondary dominant chord that acts as the dominant of the ii chord, tonicizing the supertonic. In C major, V/ii is an A major triad (A–C#–E) that resolves to D minor, and the C# is the chromatic note that creates the dominant pull.
No. Both chords sit on scale degree 6, but vi is the diatonic minor triad (A–C–E in C major) while V/ii has a raised third (A–C#–E). That single accidental turns a stable diatonic chord into a chromatic chord that must resolve to ii.
They're both secondary dominants, but they tonicize different chords. V/ii is built on scale degree 6 and resolves to ii, while V/V is built on scale degree 2 and resolves to V. The construction logic is identical: build a major triad or dominant seventh a perfect fifth above the chord you want to tonicize.
No. In minor keys the ii chord is diminished, and diminished triads can't function as a temporary tonic, so there's nothing to tonicize. V/ii is a major-key-only chord, which makes it a useful clue when you're identifying the mode of an excerpt.
Move the secondary leading tone (the raised third) up by half step to the root of ii, and resolve the seventh of V7/ii down by step. Don't double the chromatic leading tone, since doubling a tendency tone forces parallel octaves or an unresolved leading tone, both of which cost points on the part-writing FRQs.
Connect this key term to the AP exam workflow: review the course, practice questions, and check related study tools.
Review units, study guides, and course resources.
Check this vocabulary in multiple-choice context.
Apply key concepts in written AP responses.
Estimate the exam score you are working toward.
Review the highest-yield facts before practice.