diff --git a/x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestsDataLoader.java b/x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestsDataLoader.java
index 8e81d14b4dfd7..1648b965c6bab 100644
--- a/x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestsDataLoader.java
+++ b/x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestsDataLoader.java
@@ -64,6 +64,8 @@ public class CsvTestsDataLoader {
         .withSetting("languages_lookup-settings.json");
     private static final TestsDataset LANGUAGES_LOOKUP_NON_UNIQUE_KEY = LANGUAGES_LOOKUP.withIndex("languages_lookup_non_unique_key")
         .withData("languages_non_unique_key.csv");
+    private static final TestsDataset LANGUAGES_NESTED_FIELDS = LANGUAGES_LOOKUP.withIndex("languages_nested_fields")
+        .withData("languages_nested_fields.csv");
     private static final TestsDataset ALERTS = new TestsDataset("alerts");
     private static final TestsDataset UL_LOGS = new TestsDataset("ul_logs");
     private static final TestsDataset SAMPLE_DATA = new TestsDataset("sample_data");
diff --git a/x-pack/plugin/esql/qa/testFixtures/src/main/resources/languages_nested_fields.csv b/x-pack/plugin/esql/qa/testFixtures/src/main/resources/languages_nested_fields.csv
new file mode 100644
index 0000000000000..f26114245a6d3
--- /dev/null
+++ b/x-pack/plugin/esql/qa/testFixtures/src/main/resources/languages_nested_fields.csv
@@ -0,0 +1,5 @@
+_id:integer,language.id:integer,language.name:keyword,language.code:keyword
+1,1,English,EN
+2,2,French,FR
+3,3,Spanish,ES
+4,4,German,DE
diff --git a/x-pack/plugin/esql/qa/testFixtures/src/main/resources/lookup-join.csv-spec b/x-pack/plugin/esql/qa/testFixtures/src/main/resources/lookup-join.csv-spec
index 7d4f89ed920a9..8b69d97a43bcd 100644
--- a/x-pack/plugin/esql/qa/testFixtures/src/main/resources/lookup-join.csv-spec
+++ b/x-pack/plugin/esql/qa/testFixtures/src/main/resources/lookup-join.csv-spec
@@ -416,6 +416,28 @@ language_code:integer | language_name:keyword       | country:keyword
 8                     | Mv-Lang2                    | Mv-Land2
 ;
 
+###########################################################################
+# nested filed join behavior with languages_nested_fields index
+###########################################################################
+
+joinOnNestedField
+required_capability: join_lookup_v8
+
+FROM employees
+| WHERE 10000 < emp_no AND emp_no < 10005
+| EVAL language.id = emp_no % 10
+| LOOKUP JOIN languages_nested_fields ON language.id
+| SORT emp_no
+| KEEP emp_no, language.id, language.name
+;
+
+emp_no:integer | language.id:integer | language.name:keyword
+10001          | 1                   | English
+10002          | 2                   | French
+10003          | 3                   | Spanish
+10004          | 4                   | German
+;
+
 ###############################################
 # Tests with clientips_lookup index
 ###############################################