diff --git a/src/hours/resolve-common.ts b/src/hours/resolve-common.ts
index 6c44b02..788c42d 100644
--- a/src/hours/resolve-common.ts
+++ b/src/hours/resolve-common.ts
@@ -462,6 +462,22 @@ function sanctoralCommemorationPart(commemoration: Extract<Commemoration, { kind
   return { kind: 'preces', text: { text: {}, status: { la: 'missing', en: 'missing' } }, label };
 }
 
+/** An octave commemoration's own rendering — the fuller "Commemoratio
+ * Octavæ ..." Ant+V/R+collect bundle (`${id}-octave-commemoration`, e.g.
+ * christmas-day-octave-commemoration.yml), same shape and fallback
+ * pattern as sanctoralCommemorationPart. No per-saint `propers`
+ * indirection needed: an octave commemoration's id already is the base
+ * feast/saint id (`christmas-day`, `st-stephen-protomartyr`, ...),
+ * matching the proper file's own id 1:1. */
+function octaveCommemorationPart(commemoration: Extract<Commemoration, { kind: 'octave' }>): ResolvedPart {
+  const label = `Commemoration of the Octave of ${commemoration.name}`;
+  const combined = resolveCommon(`${commemoration.id}-octave-commemoration`);
+  if (combined.status.la !== 'missing' || combined.status.en !== 'missing') {
+    return { kind: 'preces', text: combined, label };
+  }
+  return { kind: 'preces', text: { text: {}, status: { la: 'missing', en: 'missing' } }, label };
+}
+
 /**
  * The day's own collect, plus one more per commemoration (calendar/
  * types.ts's LiturgicalDay.commemorations) — Lauds/Vespers say all of
@@ -475,10 +491,22 @@ function sanctoralCommemorationPart(commemoration: Extract<Commemoration, { kind
  * Amen." for the single-collect case every other hour uses today, and
  * stripping that back out per-collect to chain them properly would need
  * text surgery this doesn't attempt — so on a commemorated day, each
- * collect here renders as its own complete, separate block instead. An
- * octave commemoration never contributes anything of its own here — once
- * resolveOfficeWinner is in play, its content is already the primary
- * collect above, so a separate entry would just be a redundant repeat.
+ * collect here renders as its own complete, separate block instead.
+ *
+ * An octave commemoration only renders its own block here when
+ * `day.temporalCategory !== 'ordinary-feria'` — the same gate
+ * resolveOfficeWinner uses (see its own doc comment). On an *ordinary*
+ * octave day (e.g. an in-between day of St. Lawrence's own octave),
+ * resolveOfficeWinner has already substituted that octave's content as
+ * the primary collect above, so rendering it again here would be a
+ * redundant repeat (or worse, an honestly-"missing" duplicate for the
+ * many octaves without their own `-octave-commemoration.yml` authored).
+ * On a day the temporal identity itself keeps real standing (the
+ * Christmas Octave's own stacking days, e.g. Dec 26-31, where Christmas
+ * + Stephen + John + Holy Innocents are each merely commemorated
+ * alongside the day's own temporal office), resolveOfficeWinner does
+ * *not* touch the primary collect at all, so this is the only place
+ * these four octaves' real "Commemoratio Octavæ ..." content surfaces.
  */
 export function getDayCollects(day: LiturgicalDay): ResolvedPart[] {
   const parts: ResolvedPart[] = [{ kind: 'prayer', text: getDayCollect(day) }];
@@ -487,6 +515,8 @@ export function getDayCollects(day: LiturgicalDay): ResolvedPart[] {
       parts.push({ kind: 'prayer', text: toResolvedText(getTemporalProper(`${commemoration.id}-collect`)) });
     } else if (commemoration.kind === 'sanctoral') {
       parts.push(sanctoralCommemorationPart(commemoration));
+    } else if (commemoration.kind === 'octave' && day.temporalCategory !== 'ordinary-feria') {
+      parts.push(octaveCommemorationPart(commemoration));
     }
   }
   return parts;
diff --git a/tests/hours/vespers.test.ts b/tests/hours/vespers.test.ts
index 199eb3f..712cf45 100644
--- a/tests/hours/vespers.test.ts
+++ b/tests/hours/vespers.test.ts
@@ -157,6 +157,34 @@ describe('resolveOrdo("vespers", ...)', () => {
     expect(anne).toBeDefined();
   });
 
+  it("renders each of the Christmas Octave's own stacked 'Commemoratio Octavæ' blocks on a day the temporal office itself keeps standing", () => {
+    // 2033-12-30 -- one day past the '2033-12-29' stacking fixture already
+    // used in tests/calendar/octaves.test.ts (St. Thomas of Canterbury's
+    // day, itself outside this app's calendar so the day stays plain
+    // temporal). All four of Christmas/Stephen/John/Holy Innocents' own
+    // octaves are active and none of them wins the day outright (the
+    // temporal day itself, "privileged-feria-minor", keeps the office) --
+    // see hours/resolve-common.ts's getDayCollects, kind === 'octave'
+    // branch, and its own doc comment for why this is the one case an
+    // octave commemoration renders its own Ant+V/R+collect block here.
+    const ordo = resolveOrdo('vespers', '2033-12-30');
+    const octaveParts = ordo.parts.filter(
+      (p): p is Extract<typeof p, { kind: 'preces' }> => p.kind === 'preces' && (p.label?.includes('Octave of') ?? false),
+    );
+    expect(octaveParts.map((p) => p.label).sort()).toEqual(
+      [
+        'Commemoration of the Octave of Christmas',
+        'Commemoration of the Octave of The Holy Innocents, Martyrs',
+        'Commemoration of the Octave of St. John, Apostle and Evangelist',
+        'Commemoration of the Octave of St. Stephen, Protomartyr',
+      ].sort(),
+    );
+    for (const part of octaveParts) {
+      expect(part.text.status.la).toBe('verified');
+      expect(part.text.status.en).toBe('verified');
+    }
+  });
+
   it("renders Advent's seasonal chapter/hymn/versicle instead of the plain weekday default", () => {
     // 2025-12-02 is a Tuesday in Advent (St. Bibiana, Simplex, merely
     // commemorated — the day's own winner stays temporal either way).