diff --git a/CHANGELOG.md b/CHANGELOG.md
index 068b3dc00b85e..25a6d24d25c63 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ### Fixed
 - Fix flaky test FieldDataLoadingIT.testIndicesFieldDataCacheSizeSetting ([#19571](https://github.com/opensearch-project/OpenSearch/pull/19571))
+- Fix case-insensitive wildcard + aggregation query crash ([#19489](https://github.com/opensearch-project/OpenSearch/pull/19489))
 - Avoid primary shard failure caused by merged segment warmer exceptions ([#19436](https://github.com/opensearch-project/OpenSearch/pull/19436))
 
 ### Dependencies
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java b/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java
index fa1d88a3a6537..2b45d961ddc87 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java
@@ -39,6 +39,7 @@
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.Operations;
+import org.apache.lucene.util.automaton.TooComplexToDeterminizeException;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -92,7 +93,14 @@ public static AutomatonQuery caseInsensitiveTermQuery(Term term) {
      * Build an automaton matching a wildcard pattern, ASCII case insensitive, if the method is null, then will use {@link  MultiTermQuery#CONSTANT_SCORE_BLENDED_REWRITE}.
      */
     public static AutomatonQuery caseInsensitiveWildcardQuery(Term wildcardquery, MultiTermQuery.RewriteMethod method) {
-        return createAutomatonQuery(wildcardquery, toCaseInsensitiveWildcardAutomaton(wildcardquery), method);
+        Automaton automaton = toCaseInsensitiveWildcardAutomaton(wildcardquery);
+        try {
+            automaton = Operations.determinize(automaton, Operations.DEFAULT_DETERMINIZE_WORK_LIMIT);
+        } catch (TooComplexToDeterminizeException e) {
+            throw new RuntimeException("Wildcard query too complex to determinize for term: " + wildcardquery, e);
+        }
+        assert automaton.isDeterministic();
+        return createAutomatonQuery(wildcardquery, automaton, method);
     }
 
     /**