diff --git a/src/plugin/customParseFormat/index.js b/src/plugin/customParseFormat/index.js
index c7082833c..205c9ccb4 100644
--- a/src/plugin/customParseFormat/index.js
+++ b/src/plugin/customParseFormat/index.js
@@ -1,6 +1,6 @@
 import { u } from '../localizedFormat/utils'
 
-const formattingTokens = /(\[[^[]*\])|([-_:/.,()\s]+)|(A|a|Q|YYYY|YY?|ww?|MM?M?M?|Do|DD?|hh?|HH?|mm?|ss?|S{1,3}|z|ZZ?)/g
+const formattingTokens = /(\[[^[]*\])|([-_:/.,()\s]+)|(A|a|Q|YYYY|YY?|ww?|GGGG|WW?|MM?M?M?|Do|DD?|hh?|HH?|mm?|ss?|S{1,3}|z|ZZ?)/g
 
 const match1 = /\d/ // 0 - 9
 const match2 = /\d\d/ // 00 - 99
@@ -100,6 +100,9 @@ const expressions = {
   }],
   w: [match1to2, addInput('week')],
   ww: [match2, addInput('week')],
+  W: [match1to2, addInput('isoWeek')],
+  WW: [match2, addInput('isoWeek')],
+  GGGG: [match4, addInput('isoYear')],
   M: [match1to2, addInput('month')],
   MM: [match2, addInput('month')],
   MMM: [matchWord, function (input) {
@@ -182,9 +185,15 @@ const parseFormattedInput = (input, format, utc, dayjs) => {
   try {
     if (['x', 'X'].indexOf(format) > -1) return new Date((format === 'X' ? 1000 : 1) * input)
     const parser = makeParser(format)
+    const parserResult = parser(input)
     const {
-      year, month, day, hours, minutes, seconds, milliseconds, zone, week
-    } = parser(input)
+      month, day, hours, minutes, seconds, milliseconds, zone, week, isoYear
+    } = parserResult
+    let { year, isoWeek } = parserResult
+    year = year || isoYear
+    if (isoYear && !isoWeek) {
+      isoWeek = 1
+    }
     const now = new Date()
     const d = day || ((!year && !month) ? now.getDate() : 1)
     const y = year || now.getFullYear()
@@ -206,6 +215,9 @@ const parseFormattedInput = (input, format, utc, dayjs) => {
     newDate = new Date(y, M, d, h, m, s, ms)
     if (week) {
       newDate = dayjs(newDate).week(week).toDate()
+    } else if (isoWeek) {
+      newDate = dayjs(newDate).add(7, 'day').isoWeek(isoWeek).isoWeekday(1)
+        .toDate()
     }
     return newDate
   } catch (e) {
diff --git a/test/plugin/customParseFormat.test.js b/test/plugin/customParseFormat.test.js
index fb4030176..c299fe75a 100644
--- a/test/plugin/customParseFormat.test.js
+++ b/test/plugin/customParseFormat.test.js
@@ -8,10 +8,12 @@ import customParseFormat from '../../src/plugin/customParseFormat'
 import advancedFormat from '../../src/plugin/advancedFormat'
 import localizedFormats from '../../src/plugin/localizedFormat'
 import weekOfYear from '../../src/plugin/weekOfYear'
+import isoWeek from '../../src/plugin/isoWeek'
 
 dayjs.extend(customParseFormat)
 dayjs.extend(localizedFormats)
 dayjs.extend(weekOfYear) // test parse w, ww
+dayjs.extend(isoWeek) // test parse GGGG; parse W, WW
 
 beforeEach(() => {
   MockDate.set(new Date())
@@ -460,3 +462,26 @@ it('parse w, ww', () => {
   const format2 = 'YYYY-[w]ww'
   expect(dayjs(input2, format2).format(format1)).toBe(input2)
 })
+
+it('parse GGGG', () => {
+  const input1 = '2024'
+  const input2 = '2023'
+  const input3 = '2022'
+  const input4 = '2021'
+  const input5 = '2020'
+  const format = 'GGGG'
+  expect(dayjs(input1, format).valueOf()).toBe(moment(input1, format).valueOf())
+  expect(dayjs(input2, format).valueOf()).toBe(moment(input2, format).valueOf())
+  expect(dayjs(input3, format).valueOf()).toBe(moment(input3, format).valueOf())
+  expect(dayjs(input4, format).valueOf()).toBe(moment(input4, format).valueOf())
+  expect(dayjs(input5, format).valueOf()).toBe(moment(input5, format).valueOf())
+})
+
+it('parse W, WW', () => {
+  const input1 = '2024-W1'
+  const format1 = 'GGGG-[W]W'
+  expect(dayjs(input1, format1).valueOf()).toBe(moment(input1, format1).valueOf())
+  const input2 = '2024-W32'
+  const format2 = 'GGGG-[W]WW'
+  expect(dayjs(input2, format2).valueOf()).toBe(moment(input2, format2).valueOf())
+})