diff --git a/src/plugin/customParseFormat/index.js b/src/plugin/customParseFormat/index.js
index c7082833c..ae3e4ae7c 100644
--- a/src/plugin/customParseFormat/index.js
+++ b/src/plugin/customParseFormat/index.js
@@ -49,10 +49,13 @@ const meridiemMatch = (input, isLowerCase) => {
   if (!meridiem) {
     isAfternoon = input === (isLowerCase ? 'pm' : 'PM')
   } else {
-    for (let i = 1; i <= 24; i += 1) {
-      // todo: fix input === meridiem(i, 0, isLowerCase)
+    // Iterate over a full 24-hour range so the meridiem string for each hour is
+    // checked. The previous loop started at hour 1 and used an `i > 12` check,
+    // but a PM string first matched at i=12 (12 > 12 === false) and was misread
+    // as AM for non-English locales such as `ko` (오전/오후). (#2031)
+    for (let i = 0; i <= 23; i += 1) {
       if (input.indexOf(meridiem(i, 0, isLowerCase)) > -1) {
-        isAfternoon = i > 12
+        isAfternoon = i >= 12
         break
       }
     }
diff --git a/test/plugin/customParseFormat.test.js b/test/plugin/customParseFormat.test.js
index fb4030176..2304f09f4 100644
--- a/test/plugin/customParseFormat.test.js
+++ b/test/plugin/customParseFormat.test.js
@@ -4,6 +4,7 @@ import dayjs from '../../src'
 import '../../src/locale/ru'
 import uk from '../../src/locale/uk'
 import '../../src/locale/zh-cn'
+import '../../src/locale/ko'
 import customParseFormat from '../../src/plugin/customParseFormat'
 import advancedFormat from '../../src/plugin/advancedFormat'
 import localizedFormats from '../../src/plugin/localizedFormat'
@@ -349,6 +350,26 @@ describe('meridiem locale', () => {
   })
 })
 
+// issue 2031
+describe('parse localized meridiem (ko) in strict mode', () => {
+  const format = 'YYYY-MM-DD hh:mm A'
+  it('AM', () => {
+    expect(dayjs('2024-01-01 01:00 오전', format, 'ko', true).hour()).toBe(1)
+  })
+  it('PM', () => {
+    expect(dayjs('2024-01-01 01:00 오후', format, 'ko', true).hour()).toBe(13)
+  })
+  it('noon (12 PM)', () => {
+    expect(dayjs('2024-01-01 12:00 오후', format, 'ko', true).hour()).toBe(12)
+  })
+  it('midnight (12 AM)', () => {
+    expect(dayjs('2024-01-01 12:00 오전', format, 'ko', true).hour()).toBe(0)
+  })
+  it('11 PM', () => {
+    expect(dayjs('2024-01-01 11:00 오후', format, 'ko', true).hour()).toBe(23)
+  })
+})
+
 it('parse a string for MMM month format with underscore delimiter', () => {
   const input = 'Jan_2021'
   const format = 'MMM_YYYY'