diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index daf1887e84d..2f391e4f5e0 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -204,6 +204,8 @@ Improvements
 
 * GITHUB#13043: Support getMaxScore of ConjunctionScorer for non top level scoring clause. (Shintaro Murakami)
 
+* GITHUB#13055: Make DEFAULT_STOP_TAGS in KoreanPartOfSpeechStopFilter immutable (Dmitry Cherniachenko)
+
 Optimizations
 ---------------------
 
diff --git a/lucene/analysis/nori/src/java/org/apache/lucene/analysis/ko/KoreanPartOfSpeechStopFilter.java b/lucene/analysis/nori/src/java/org/apache/lucene/analysis/ko/KoreanPartOfSpeechStopFilter.java
index 3480e376788..553fa262a87 100644
--- a/lucene/analysis/nori/src/java/org/apache/lucene/analysis/ko/KoreanPartOfSpeechStopFilter.java
+++ b/lucene/analysis/nori/src/java/org/apache/lucene/analysis/ko/KoreanPartOfSpeechStopFilter.java
@@ -16,6 +16,7 @@
  */
 package org.apache.lucene.analysis.ko;
 
+import java.util.Collections;
 import java.util.EnumSet;
 import java.util.Set;
 import org.apache.lucene.analysis.FilteringTokenFilter;
@@ -33,37 +34,38 @@ public final class KoreanPartOfSpeechStopFilter extends FilteringTokenFilter {
 
   /** Default list of tags to filter. */
   public static final Set<POS.Tag> DEFAULT_STOP_TAGS =
-      EnumSet.of(
-          POS.Tag.EP,
-          POS.Tag.EF,
-          POS.Tag.EC,
-          POS.Tag.ETN,
-          POS.Tag.ETM,
-          POS.Tag.IC,
-          POS.Tag.JKS,
-          POS.Tag.JKC,
-          POS.Tag.JKG,
-          POS.Tag.JKO,
-          POS.Tag.JKB,
-          POS.Tag.JKV,
-          POS.Tag.JKQ,
-          POS.Tag.JX,
-          POS.Tag.JC,
-          POS.Tag.MAG,
-          POS.Tag.MAJ,
-          POS.Tag.MM,
-          POS.Tag.SP,
-          POS.Tag.SSC,
-          POS.Tag.SSO,
-          POS.Tag.SC,
-          POS.Tag.SE,
-          POS.Tag.XPN,
-          POS.Tag.XSA,
-          POS.Tag.XSN,
-          POS.Tag.XSV,
-          POS.Tag.UNA,
-          POS.Tag.NA,
-          POS.Tag.VSV);
+      Collections.unmodifiableSet(
+          EnumSet.of(
+              POS.Tag.EP,
+              POS.Tag.EF,
+              POS.Tag.EC,
+              POS.Tag.ETN,
+              POS.Tag.ETM,
+              POS.Tag.IC,
+              POS.Tag.JKS,
+              POS.Tag.JKC,
+              POS.Tag.JKG,
+              POS.Tag.JKO,
+              POS.Tag.JKB,
+              POS.Tag.JKV,
+              POS.Tag.JKQ,
+              POS.Tag.JX,
+              POS.Tag.JC,
+              POS.Tag.MAG,
+              POS.Tag.MAJ,
+              POS.Tag.MM,
+              POS.Tag.SP,
+              POS.Tag.SSC,
+              POS.Tag.SSO,
+              POS.Tag.SC,
+              POS.Tag.SE,
+              POS.Tag.XPN,
+              POS.Tag.XSA,
+              POS.Tag.XSN,
+              POS.Tag.XSV,
+              POS.Tag.UNA,
+              POS.Tag.NA,
+              POS.Tag.VSV));
 
   /**
    * Create a new {@link KoreanPartOfSpeechStopFilter} with the default list of stop tags {@link