diff --git a/src/locale/is.js b/src/locale/is.js
index 7b1409e67..1d0d0938a 100644
--- a/src/locale/is.js
+++ b/src/locale/is.js
@@ -1,5 +1,44 @@
 // Icelandic [is]
-import dayjs from 'dayjs'
+import dayjs from 'dayjs';
+
+const texts = {
+  s: ['nokkrar sekúndur', 'nokkrar sekúndur', 'nokkrum sekúndum'],
+  m: ['mínúta', 'mínútu', 'mínútu'],
+  mm: ['mínútur', 'mínútur', 'mínútum'],
+  h: ['klukkustund', 'klukkustund', 'klukkustund'],
+  hh: ['klukkustundir', 'klukkustundir', 'klukkustundum'],
+  d: ['dagur', 'dag', 'degi'],
+  dd: ['dagar', 'daga', 'dögum'],
+  M: ['mánuður', 'mánuð', 'mánuði'],
+  MM: ['mánuðir', 'mánuði', 'mánuðum'],
+  y: ['ár', 'ár', 'ári'],
+  yy: ['ár', 'ár', 'árum']
+}
+
+function resolveTemplate(key, number, isFuture, withoutSuffix) {
+  const suffixIndex = isFuture
+    ? 1
+    : 2
+
+  const index = withoutSuffix
+    ? 0
+    : suffixIndex
+
+  const keyShouldBeSingular = key.length === 2 && number % 10 === 1
+
+  const correctedKey = keyShouldBeSingular ? key[0] : key
+  const unitText = texts[correctedKey]
+  const text = unitText[index]
+  return key.length === 1
+    ? text
+    : `%d ${text}`
+}
+
+function relativeTimeFormatter(number, withoutSuffix, key, isFuture) {
+  const template = resolveTemplate(key, number, isFuture, withoutSuffix)
+
+  return template.replace('%d', number)
+}
 
 const locale = {
   name: 'is',
@@ -17,10 +56,24 @@ const locale = {
     LL: 'D. MMMM YYYY',
     LLL: 'D. MMMM YYYY [kl.] H:mm',
     LLLL: 'dddd, D. MMMM YYYY [kl.] H:mm'
+  },
+  relativeTime: {
+    future: 'eftir %s',
+    past: 'fyrir %s síðan',
+    s: relativeTimeFormatter,
+    m: relativeTimeFormatter,
+    mm: relativeTimeFormatter,
+    h: relativeTimeFormatter,
+    hh: relativeTimeFormatter,
+    d: relativeTimeFormatter,
+    dd: relativeTimeFormatter,
+    M: relativeTimeFormatter,
+    MM: relativeTimeFormatter,
+    y: relativeTimeFormatter,
+    yy: relativeTimeFormatter
   }
 }
 
 dayjs.locale(locale, null, true)
 
 export default locale
-
diff --git a/test/locale/is.test.js b/test/locale/is.test.js
new file mode 100644
index 000000000..0198b0f2b
--- /dev/null
+++ b/test/locale/is.test.js
@@ -0,0 +1,115 @@
+import MockDate from 'mockdate'
+import moment from 'moment'
+import dayjs from '../../src'
+import '../../src/locale/is'
+import relativeTime from '../../src/plugin/relativeTime'
+
+dayjs.extend(relativeTime)
+
+beforeEach(() => {
+  MockDate.set(new Date())
+})
+
+afterEach(() => {
+  MockDate.reset()
+})
+
+const expectations = [
+  [1, 's', 'nokkrar sekúndur', 'fyrir nokkrum sekúndum síðan', 'eftir nokkrar sekúndur'],
+  [1, 'm', 'mínúta', 'fyrir mínútu síðan', 'eftir mínútu'],
+  [1, 'h', 'klukkustund', 'fyrir klukkustund síðan', 'eftir klukkustund'],
+  [1, 'd', 'dagur', 'fyrir degi síðan', 'eftir dag'],
+  [1, 'M', 'mánuður', 'fyrir mánuði síðan', 'eftir mánuð'],
+  [1, 'y', 'ár', 'fyrir ári síðan', 'eftir ár'],
+  [2, 'm', '2 mínútur', 'fyrir 2 mínútum síðan', 'eftir 2 mínútur'],
+  [2, 'h', '2 klukkustundir', 'fyrir 2 klukkustundum síðan', 'eftir 2 klukkustundir'],
+  [2, 'd', '2 dagar', 'fyrir 2 dögum síðan', 'eftir 2 daga'],
+  [2, 'M', '2 mánuðir', 'fyrir 2 mánuðum síðan', 'eftir 2 mánuði'],
+  [2, 'y', '2 ár', 'fyrir 2 árum síðan', 'eftir 2 ár'],
+  [21, 'm', '21 mínúta', 'fyrir 21 mínútu síðan', 'eftir 21 mínútu'],
+  [21, 'h', '21 klukkustund', 'fyrir 21 klukkustund síðan', 'eftir 21 klukkustund'],
+  [21, 'd', '21 dagur', 'fyrir 21 degi síðan', 'eftir 21 dag'],
+  [21, 'y', '21 ár', 'fyrir 21 ári síðan', 'eftir 21 ár']
+]
+
+describe('moment compatibility', () => {
+  it('without suffix', () => {
+    expectations.forEach((expectation) => {
+      const [offset, unit, expectationWithoutSuffix] = expectation
+
+      const momentResult = moment()
+        .add(offset, unit)
+        .locale('is')
+        .fromNow(true)
+
+      expect(expectationWithoutSuffix).toBe(momentResult)
+    })
+  })
+
+  it('past', () => {
+    expectations.forEach((expectation) => {
+      const [offset, unit, , pastExpectation] = expectation
+
+      const momentResult = moment()
+        .add(-offset, unit)
+        .locale('is')
+        .fromNow()
+
+      expect(pastExpectation).toBe(momentResult)
+    })
+  })
+
+  it('future', () => {
+    expectations.forEach((expectation) => {
+      const [offset, unit, , , futureExpectation] = expectation
+
+      const momentResult = moment()
+        .add(offset, unit)
+        .locale('is')
+        .fromNow()
+
+      expect(futureExpectation).toBe(momentResult)
+    })
+  })
+})
+
+describe('Icelandic output matches moment output', () => {
+  it('without suffix', () => {
+    expectations.forEach((expectation) => {
+      const [offset, unit, expectationWithoutSuffix] = expectation
+
+      const result = dayjs()
+        .add(offset, unit)
+        .locale('is')
+        .fromNow(true)
+
+      expect(result).toBe(expectationWithoutSuffix)
+    })
+  })
+
+  it('past', () => {
+    expectations.forEach((expectation) => {
+      const [offset, unit, , pastExpectation] = expectation
+
+      const result = dayjs()
+        .add(-offset, unit)
+        .locale('is')
+        .fromNow()
+
+      expect(result).toBe(pastExpectation)
+    })
+  })
+
+  it('future', () => {
+    expectations.forEach((expectation) => {
+      const [offset, unit, , , futureExpectation] = expectation
+
+      const result = dayjs()
+        .add(offset, unit)
+        .locale('is')
+        .fromNow()
+
+      expect(result).toBe(futureExpectation)
+    })
+  })
+})