diff --git a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/TextMeasureCache.h b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/TextMeasureCache.h
index cb3a6000c30d..f062132f2741 100644
--- a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/TextMeasureCache.h
+++ b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/TextMeasureCache.h
@@ -66,6 +66,10 @@ class TextMeasureCacheKey final {
   AttributedString attributedString{};
   ParagraphAttributes paragraphAttributes{};
   LayoutConstraints layoutConstraints{};
+  // The measured size depends on the pixel scale factor because layout metrics
+  // are rounded to the pixel grid. Two otherwise-identical measures at different
+  // densities are not interchangeable, so the scale factor is part of the key.
+  Float pointScaleFactor{};
 };
 
 // The Key type that is used for Line Measure Cache.
@@ -87,6 +91,9 @@ class PreparedTextCacheKey final {
   AttributedString attributedString{};
   ParagraphAttributes paragraphAttributes{};
   LayoutConstraints layoutConstraints{};
+  // A prepared layout is rounded to the pixel grid, so it is only reusable at
+  // the pixel scale factor it was laid out at.
+  Float pointScaleFactor{};
 };
 
 /*
@@ -252,7 +259,8 @@ inline size_t attributedStringHashDisplayWise(const AttributedString &attributed
 inline bool operator==(const TextMeasureCacheKey &lhs, const TextMeasureCacheKey &rhs)
 {
   return areAttributedStringsEquivalentLayoutWise(lhs.attributedString, rhs.attributedString) &&
-      lhs.paragraphAttributes == rhs.paragraphAttributes && lhs.layoutConstraints == rhs.layoutConstraints;
+      lhs.paragraphAttributes == rhs.paragraphAttributes && lhs.layoutConstraints == rhs.layoutConstraints &&
+      floatEquality(lhs.pointScaleFactor, rhs.pointScaleFactor);
 }
 
 inline bool operator==(const LineMeasureCacheKey &lhs, const LineMeasureCacheKey &rhs)
@@ -264,7 +272,8 @@ inline bool operator==(const LineMeasureCacheKey &lhs, const LineMeasureCacheKey
 inline bool operator==(const PreparedTextCacheKey &lhs, const PreparedTextCacheKey &rhs)
 {
   return areAttributedStringsEquivalentDisplayWise(lhs.attributedString, rhs.attributedString) &&
-      lhs.paragraphAttributes == rhs.paragraphAttributes && lhs.layoutConstraints == rhs.layoutConstraints;
+      lhs.paragraphAttributes == rhs.paragraphAttributes && lhs.layoutConstraints == rhs.layoutConstraints &&
+      floatEquality(lhs.pointScaleFactor, rhs.pointScaleFactor);
 }
 
 } // namespace facebook::react
@@ -276,7 +285,10 @@ struct hash<facebook::react::TextMeasureCacheKey> {
   size_t operator()(const facebook::react::TextMeasureCacheKey &key) const
   {
     return facebook::react::hash_combine(
-        attributedStringHashLayoutWise(key.attributedString), key.paragraphAttributes, key.layoutConstraints);
+        attributedStringHashLayoutWise(key.attributedString),
+        key.paragraphAttributes,
+        key.layoutConstraints,
+        key.pointScaleFactor);
   }
 };
 
@@ -294,7 +306,10 @@ struct hash<facebook::react::PreparedTextCacheKey> {
   size_t operator()(const facebook::react::PreparedTextCacheKey &key) const
   {
     return facebook::react::hash_combine(
-        attributedStringHashDisplayWise(key.attributedString), key.paragraphAttributes, key.layoutConstraints);
+        attributedStringHashDisplayWise(key.attributedString),
+        key.paragraphAttributes,
+        key.layoutConstraints,
+        key.pointScaleFactor);
   }
 };
 
diff --git a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.cpp b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.cpp
index ce6ecb15373a..99886999293d 100644
--- a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.cpp
@@ -193,7 +193,8 @@ TextMeasurement TextLayoutManager::measure(
       : textMeasureCache_.get(
             {.attributedString = attributedString,
              .paragraphAttributes = paragraphAttributes,
-             .layoutConstraints = layoutConstraints},
+             .layoutConstraints = layoutConstraints,
+             .pointScaleFactor = layoutContext.pointScaleFactor},
             std::move(measureText));
 
   measurement.size = layoutConstraints.clamp(measurement.size);
@@ -315,7 +316,8 @@ TextLayoutManager::PreparedTextLayout TextLayoutManager::prepareLayout(
   const auto [key, preparedText] = preparedTextCache_.getWithKey(
       {.attributedString = attributedString,
        .paragraphAttributes = paragraphAttributes,
-       .layoutConstraints = layoutConstraints},
+       .layoutConstraints = layoutConstraints,
+       .pointScaleFactor = layoutContext.pointScaleFactor},
       [&]() {
         const auto& fabricUIManager =
             contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
diff --git a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/ios/react/renderer/textlayoutmanager/TextLayoutManager.mm b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/ios/react/renderer/textlayoutmanager/TextLayoutManager.mm
index cddafb5a6ef2..82cad8fd2eed 100644
--- a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/ios/react/renderer/textlayoutmanager/TextLayoutManager.mm
+++ b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/ios/react/renderer/textlayoutmanager/TextLayoutManager.mm
@@ -43,7 +43,8 @@
       measurement = textMeasureCache_.get(
           {.attributedString = attributedString,
            .paragraphAttributes = paragraphAttributes,
-           .layoutConstraints = layoutConstraints},
+           .layoutConstraints = layoutConstraints,
+           .pointScaleFactor = layoutContext.pointScaleFactor},
           [&]() {
             auto telemetry = TransactionTelemetry::threadLocalTelemetry();
             if (telemetry) {
diff --git a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/tests/TextLayoutManagerTest.cpp b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/tests/TextLayoutManagerTest.cpp
index 8d1152bcc9aa..bd0a053f64bc 100644
--- a/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/tests/TextLayoutManagerTest.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/textlayoutmanager/tests/TextLayoutManagerTest.cpp
@@ -44,3 +44,56 @@ TEST(TextLayoutManagerTest, maxFontSizeMultiplierAffectsLayoutCacheHash) {
   EXPECT_NE(
       textAttributesHashLayoutWise(lhs), textAttributesHashLayoutWise(rhs));
 }
+
+// Measurements are rounded to the pixel grid, so a measurement cached at one
+// pixel scale factor must not satisfy a lookup at another. Keys that differ
+// only by pointScaleFactor must compare unequal.
+TEST(TextLayoutManagerTest, pointScaleFactorAffectsTextMeasureCacheEquality) {
+  TextMeasureCacheKey lhs;
+  TextMeasureCacheKey rhs;
+
+  lhs.pointScaleFactor = 2.0;
+  rhs.pointScaleFactor = 1.6;
+  EXPECT_FALSE(lhs == rhs);
+
+  rhs.pointScaleFactor = 2.0;
+  EXPECT_TRUE(lhs == rhs);
+}
+
+TEST(TextLayoutManagerTest, pointScaleFactorAffectsTextMeasureCacheHash) {
+  TextMeasureCacheKey lhs;
+  TextMeasureCacheKey rhs;
+
+  lhs.pointScaleFactor = 2.0;
+  rhs.pointScaleFactor = 1.6;
+
+  EXPECT_NE(
+      std::hash<TextMeasureCacheKey>{}(lhs),
+      std::hash<TextMeasureCacheKey>{}(rhs));
+}
+
+// Same invariant for the prepared-text cache: a prepared layout is pixel-grid
+// rounded and is only reusable at the pixel scale factor it was prepared at.
+TEST(TextLayoutManagerTest, pointScaleFactorAffectsPreparedTextCacheEquality) {
+  PreparedTextCacheKey lhs;
+  PreparedTextCacheKey rhs;
+
+  lhs.pointScaleFactor = 2.0;
+  rhs.pointScaleFactor = 1.6;
+  EXPECT_FALSE(lhs == rhs);
+
+  rhs.pointScaleFactor = 2.0;
+  EXPECT_TRUE(lhs == rhs);
+}
+
+TEST(TextLayoutManagerTest, pointScaleFactorAffectsPreparedTextCacheHash) {
+  PreparedTextCacheKey lhs;
+  PreparedTextCacheKey rhs;
+
+  lhs.pointScaleFactor = 2.0;
+  rhs.pointScaleFactor = 1.6;
+
+  EXPECT_NE(
+      std::hash<PreparedTextCacheKey>{}(lhs),
+      std::hash<PreparedTextCacheKey>{}(rhs));
+}
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api
index 23da100989c0..e54e4bb6acbb 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api
@@ -4129,6 +4129,7 @@ class facebook::react::PointerHoverTracker {
 
 class facebook::react::PreparedTextCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
@@ -5064,6 +5065,7 @@ class facebook::react::TextLayoutManager {
 
 class facebook::react::TextMeasureCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api
index 12885e3d63cd..fbaf6d503d9d 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api
@@ -3973,6 +3973,7 @@ class facebook::react::PointerHoverTracker {
 
 class facebook::react::PreparedTextCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
@@ -4890,6 +4891,7 @@ class facebook::react::TextLayoutManager {
 
 class facebook::react::TextMeasureCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api
index c5c78b10c55d..cce1cbacb787 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api
@@ -4126,6 +4126,7 @@ class facebook::react::PointerHoverTracker {
 
 class facebook::react::PreparedTextCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
@@ -5055,6 +5056,7 @@ class facebook::react::TextLayoutManager {
 
 class facebook::react::TextMeasureCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api
index 3dfdc05855de..2a078f3c4408 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api
@@ -6316,6 +6316,7 @@ class facebook::react::PointerHoverTracker {
 
 class facebook::react::PreparedTextCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
@@ -7283,6 +7284,7 @@ class facebook::react::TextLayoutManager {
 
 class facebook::react::TextMeasureCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api
index e49d4cdde961..c2aa6cdfc4ed 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api
@@ -6188,6 +6188,7 @@ class facebook::react::PointerHoverTracker {
 
 class facebook::react::PreparedTextCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
@@ -7137,6 +7138,7 @@ class facebook::react::TextLayoutManager {
 
 class facebook::react::TextMeasureCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api
index b89188d3b837..040d1db716a8 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api
@@ -6313,6 +6313,7 @@ class facebook::react::PointerHoverTracker {
 
 class facebook::react::PreparedTextCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
@@ -7274,6 +7275,7 @@ class facebook::react::TextLayoutManager {
 
 class facebook::react::TextMeasureCacheKey {
   public facebook::react::AttributedString attributedString;
+  public facebook::react::Float pointScaleFactor;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
 }
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api
index 6d18214f9b43..d4113b38f16e 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api
@@ -2732,6 +2732,7 @@ class facebook::react::PointerHoverTracker {
 }
 
 class facebook::react::PreparedTextCacheKey {
+  public Float pointScaleFactor;
   public facebook::react::AttributedString attributedString;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
@@ -3554,6 +3555,7 @@ class facebook::react::TextInputState {
 }
 
 class facebook::react::TextMeasureCacheKey {
+  public Float pointScaleFactor;
   public facebook::react::AttributedString attributedString;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api
index 2d462c2c4aeb..6908e99301b7 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api
@@ -2616,6 +2616,7 @@ class facebook::react::PointerHoverTracker {
 }
 
 class facebook::react::PreparedTextCacheKey {
+  public Float pointScaleFactor;
   public facebook::react::AttributedString attributedString;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
@@ -3420,6 +3421,7 @@ class facebook::react::TextInputState {
 }
 
 class facebook::react::TextMeasureCacheKey {
+  public Float pointScaleFactor;
   public facebook::react::AttributedString attributedString;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api
index 5d4384fa8356..d64d649e6a7e 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api
@@ -2729,6 +2729,7 @@ class facebook::react::PointerHoverTracker {
 }
 
 class facebook::react::PreparedTextCacheKey {
+  public Float pointScaleFactor;
   public facebook::react::AttributedString attributedString;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;
@@ -3545,6 +3546,7 @@ class facebook::react::TextInputState {
 }
 
 class facebook::react::TextMeasureCacheKey {
+  public Float pointScaleFactor;
   public facebook::react::AttributedString attributedString;
   public facebook::react::LayoutConstraints layoutConstraints;
   public facebook::react::ParagraphAttributes paragraphAttributes;