diff --git a/lib/bb/parse/ast.py b/lib/bb/parse/ast.py
index 5f2aaadfb..d5d53a7c7 100644
--- a/lib/bb/parse/ast.py
+++ b/lib/bb/parse/ast.py
@@ -55,7 +55,8 @@ class IncludeAllNode(AstNode):
         s = data.expand(self.what_file)
         logger.debug2("CONF %s:%s: including %s", self.filename, self.lineno, s)
 
-        for path in data.getVar("BBPATH").split(":"):
+        # A directory listed more than once in BBPATH is only searched once
+        for path in dict.fromkeys(data.getVar("BBPATH").split(":")):
             bb.parse.ConfHandler.include(self.filename, os.path.join(path, s), self.lineno, data, False)
 
 class ExportNode(AstNode):
diff --git a/lib/bb/tests/parse.py b/lib/bb/tests/parse.py
index 6ac2137e0..cd8f02388 100644
--- a/lib/bb/tests/parse.py
+++ b/lib/bb/tests/parse.py
@@ -511,6 +511,26 @@ EXTRA_OECONF:append = " foobar"
             test_helper("include_all some.conf", " bar foo")
             test_helper("include_all some3.conf", " foobar")
 
+    def test_include_all_duplicate_bbpath(self):
+        # A directory listed more than once in BBPATH is only searched once
+        with tempfile.TemporaryDirectory() as tempdir:
+            os.makedirs(tempdir + "/conf1")
+            os.makedirs(tempdir + "/conf2")
+            with open(tempdir + "/conf1/some.conf", "w") as f:
+                f.write(self.someconf1)
+            with open(tempdir + "/conf2/some.conf", "w") as f:
+                f.write(self.someconf2)
+
+            self.d.setVar("BBPATH", ":".join([tempdir + "/conf1", tempdir + "/conf2", tempdir + "/conf1"]))
+
+            with self.parsehelper("include_all some.conf") as f:
+                with self.assertLogs("BitBake.Parsing", level="WARNING") as logs:
+                    d = bb.parse.handle(f.name, bb.data.createCopy(self.d))['']
+                    # assertLogs fails if nothing is logged at all
+                    bb.parse.logger.warning("parse done")
+            self.assertEqual(d.getVar("EXTRA_OECONF"), " foo bar")
+            self.assertEqual(logs.output, ["WARNING:BitBake.Parsing:parse done"])
+
     def test_file_variables(self):
         # Tests the values of FILE and __BB_RECIPE_FILE in different
         # combinations of bbappends, includes, and inherits