diff --git a/spring-data-jpa/src/main/antlr4/org/springframework/data/jpa/repository/query/Jpql.g4 b/spring-data-jpa/src/main/antlr4/org/springframework/data/jpa/repository/query/Jpql.g4
index 271e9d168b..140916515f 100644
--- a/spring-data-jpa/src/main/antlr4/org/springframework/data/jpa/repository/query/Jpql.g4
+++ b/spring-data-jpa/src/main/antlr4/org/springframework/data/jpa/repository/query/Jpql.g4
@@ -428,6 +428,7 @@ string_expression
     | aggregate_expression
     | case_expression
     | function_invocation
+    | string_expression '||' string_expression
     | '(' subquery ')'
     ;
 
diff --git a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpqlQueryRenderer.java b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpqlQueryRenderer.java
index 7ff5a6f393..13b2bd7fd4 100644
--- a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpqlQueryRenderer.java
+++ b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpqlQueryRenderer.java
@@ -1527,6 +1527,11 @@ public List<JpaQueryParsingToken> visitString_expression(JpqlParser.String_expre
 			tokens.addAll(visit(ctx.case_expression()));
 		} else if (ctx.function_invocation() != null) {
 			tokens.addAll(visit(ctx.function_invocation()));
+		} else if (ctx.string_expression() != null) {
+
+			tokens.addAll(visit(ctx.string_expression(0)));
+			tokens.add(new JpaQueryParsingToken("||"));
+			tokens.addAll(visit(ctx.string_expression(1)));
 		} else if (ctx.subquery() != null) {
 
 			tokens.add(TOKEN_OPEN_PAREN);
diff --git a/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryRendererTests.java b/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryRendererTests.java
index 0feaf2cdde..e2cc7e5105 100644
--- a/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryRendererTests.java
+++ b/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryRendererTests.java
@@ -1600,4 +1600,14 @@ void newShouldBeLegalAsPartOfAStateFieldPathExpression() {
 				ORDER BY j.id
 				""");
 	}
+
+	@Test // GH-3136
+	void doublePipeShouldBeValidAsAStringConcatOperator() {
+
+		assertQuery("""
+				select e.name || ' ' || e.title
+				from Employee e
+				""");
+	}
+
 }
diff --git a/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/JpqlQueryRendererTests.java b/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/JpqlQueryRendererTests.java
index d738ccac37..1eedc0b9da 100644
--- a/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/JpqlQueryRendererTests.java
+++ b/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/JpqlQueryRendererTests.java
@@ -983,4 +983,13 @@ void newShouldBeLegalAsPartOfAStateFieldPathExpression() {
 				ORDER BY j.id
 				""");
 	}
+
+	@Test // GH-3136
+	void doublePipeShouldBeValidAsAStringConcatOperator() {
+
+		assertQuery("""
+				select e.name || ' ' || e.title
+				from Employee e
+				""");
+	}
 }