diff --git a/features.txt b/features.txt
index 812c13a0cf..fae5d364fa 100644
--- a/features.txt
+++ b/features.txt
@@ -178,6 +178,10 @@ coalesce-expression
 # https://github.com/tc39-transfer/proposal-intl-displaynames
 Intl.DisplayNames
 
+# Intl.NumberFormat V3
+# https://github.com/tc39/proposal-intl-numberformat-v3
+Intl.NumberFormat-v3
+
 # Promise.any
 # https://github.com/tc39/proposal-promise-any
 Promise.any
diff --git a/test/intl402/NumberFormat/constructor-options-throwing-getters-rounding-mode.js b/test/intl402/NumberFormat/constructor-options-throwing-getters-rounding-mode.js
new file mode 100644
index 0000000000..a6eedd84f2
--- /dev/null
+++ b/test/intl402/NumberFormat/constructor-options-throwing-getters-rounding-mode.js
@@ -0,0 +1,17 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-initializenumberformat
+description: >
+  Exception from accessing the "roundingMode" option for the NumberFormat
+  constructor should be propagated to the caller
+features: [Intl.NumberFormat-v3]
+---*/
+
+assert.throws(Test262Error, function() {
+  new Intl.NumberFormat('en', {
+    get roundingMode() {
+      throw new Test262Error();
+    }
+  });
+});
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-ceil.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-ceil.js
new file mode 100644
index 0000000000..636789e188
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-ceil.js
@@ -0,0 +1,32 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "ceil", rounding tends toward positive infinity
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'ceil', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.2',
+    '1.15': '1.2',
+    '1.1999': '1.2',
+    '1.25': '1.3',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.1',
+    '-1.1999': '-1.1',
+    '-1.25': '-1.2'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-expand.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-expand.js
new file mode 100644
index 0000000000..bba6e369b2
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-expand.js
@@ -0,0 +1,32 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "expand", rounding tends away from zero
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'expand', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.2',
+    '1.15': '1.2',
+    '1.1999': '1.2',
+    '1.25': '1.3',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.2',
+    '-1.15': '-1.2',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.3'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-floor.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-floor.js
new file mode 100644
index 0000000000..ca5797b9d4
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-floor.js
@@ -0,0 +1,32 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "floor", rounding tends toward negative infinity
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'floor', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.1',
+    '1.1999': '1.1',
+    '1.25': '1.2',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.2',
+    '-1.15': '-1.2',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.3'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-ceil.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-ceil.js
new file mode 100644
index 0000000000..3739c7e62a
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-ceil.js
@@ -0,0 +1,33 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "halfExpand", rounding tends toward the closest value
+  with ties tending toward positive infinity
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'halfCeil', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.2',
+    '1.1999': '1.2',
+    '1.25': '1.3',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.1',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.2'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-even.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-even.js
new file mode 100644
index 0000000000..85fdd0c15c
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-even.js
@@ -0,0 +1,34 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "halfEven", rounding tends toward the closest value
+  with ties tending toward the value with even cardinality
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'halfEven', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.2',
+    '1.1999': '1.2',
+    '1.25': '1.2',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.2',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.2'
+  }
+);
+
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-expand.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-expand.js
new file mode 100644
index 0000000000..c89b1fc9f3
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-expand.js
@@ -0,0 +1,33 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "halfExpand", rounding tends toward the closest value
+  with ties tending away from zero
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'halfExpand', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.2',
+    '1.1999': '1.2',
+    '1.25': '1.3',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.2',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.3'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-floor.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-floor.js
new file mode 100644
index 0000000000..96242d6864
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-floor.js
@@ -0,0 +1,33 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "halfFloor", rounding tends toward the closest value
+  with ties tending toward negative infinity
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'halfFloor', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.1',
+    '1.1999': '1.2',
+    '1.25': '1.2',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.2',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.3'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-trunc.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-trunc.js
new file mode 100644
index 0000000000..0d73c4397d
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-half-trunc.js
@@ -0,0 +1,33 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "halfTrunc", rounding tends toward the closest value
+  with ties tending toward zero
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'halfTrunc', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.1',
+    '1.1999': '1.2',
+    '1.25': '1.2',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.1',
+    '-1.1999': '-1.2',
+    '-1.25': '-1.2'
+  }
+);
diff --git a/test/intl402/NumberFormat/prototype/format/format-rounding-mode-trunc.js b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-trunc.js
new file mode 100644
index 0000000000..e64f5c2eaa
--- /dev/null
+++ b/test/intl402/NumberFormat/prototype/format/format-rounding-mode-trunc.js
@@ -0,0 +1,32 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-intl.numberformat.prototype.format
+description: >
+  When roundingMode is "trunc", rounding tends toward zero
+features: [Intl.NumberFormat-v3]
+includes: [testIntl.js]
+---*/
+
+var locales = [
+  new Intl.NumberFormat().resolvedOptions().locale, 'ar', 'de', 'th', 'ja'
+];
+var numberingSystems = ['arab', 'latn', 'thai', 'hanidec'];
+
+testNumberFormat(
+  locales,
+  numberingSystems,
+  {useGrouping: false, roundingMode: 'trunc', maximumSignificantDigits: 2},
+  {
+    '1.101': '1.1',
+    '1.15': '1.1',
+    '1.1999': '1.1',
+    '1.25': '1.2',
+    '0': '0',
+    '-0': '-0',
+    '-1.101': '-1.1',
+    '-1.15': '-1.1',
+    '-1.1999': '-1.1',
+    '-1.25': '-1.2'
+  }
+);