diff --git a/esphome/platformio/library.py b/esphome/platformio/library.py
index 291bedb5cd..0ffac65e0d 100644
--- a/esphome/platformio/library.py
+++ b/esphome/platformio/library.py
@@ -292,6 +292,12 @@ def collect_filtered_files(src_dir: PathType, src_filters: list[str]) -> list[st
                 for root, _, files in os.walk(item):
                     matched.extend([str(Path(root) / f) for f in files])
 
+        # glob keeps the pattern's literal separators for non-wildcard path
+        # components, so on Windows the same file can surface with different
+        # separators depending on where the wildcards sit; normalize so the
+        # include/exclude set operations below compare equal paths.
+        matched = [os.path.normpath(m) for m in matched]
+
         # FILTER_REGEX only ever captures "+" or "-", so the else is the "-" case.
         if sign == "+":
             selected.update(matched)
diff --git a/tests/unit_tests/test_espidf_component.py b/tests/unit_tests/test_espidf_component.py
index a50024b8e9..055e9c8502 100644
--- a/tests/unit_tests/test_espidf_component.py
+++ b/tests/unit_tests/test_espidf_component.py
@@ -1,3 +1,4 @@
+import glob
 import hashlib
 import json
 import os
@@ -86,6 +87,48 @@ def test_collect_filtered_files_exclude(tmp_path):
     assert str(f2) not in result
 
 
+def test_collect_filtered_files_exclude_pattern_in_subdir(tmp_path):
+    src = tmp_path / "lib" / "src"
+    src.mkdir(parents=True)
+    kept = src / "a.c"
+    excluded = src / "hasty.c"
+    kept.write_text("int a;")
+    excluded.write_text("int b;")
+
+    result = collect_filtered_files(tmp_path, ["+<lib/src/*.c>", "-<lib/src/hasty.c>"])
+    assert str(kept) in result
+    assert str(excluded) not in result
+
+
+def test_collect_filtered_files_exclude_unnormalized_glob_output(tmp_path, monkeypatch):
+    # On Windows, glob keeps the pattern's literal separators for non-wildcard
+    # path components, so the "+" wildcard pattern and the "-" literal pattern
+    # yield the same file spelled differently and the exclude set difference
+    # misses it. Backslash is a regular filename character on POSIX (such paths
+    # fail the final is_file filter), so reproduce the unnormalized-output
+    # mismatch portably with dot segments, which normpath also collapses.
+    src = tmp_path / "lib" / "src"
+    src.mkdir(parents=True)
+    kept = src / "a.c"
+    excluded = src / "hasty.c"
+    kept.write_text("int a;")
+    excluded.write_text("int b;")
+
+    real_glob = glob.glob
+
+    def unnormalized_glob(pattern, recursive=False):
+        if "*" in pattern:
+            base = str(tmp_path)
+            return [base + "/lib/./src/a.c", base + "/lib/./src/hasty.c"]
+        return real_glob(pattern, recursive=recursive)
+
+    monkeypatch.setattr(glob, "glob", unnormalized_glob)
+
+    result = collect_filtered_files(tmp_path, ["+<lib/src/*.c>", "-<lib/src/hasty.c>"])
+    assert [Path(r).name for r in result] == ["a.c"]
+    assert str(kept) in result
+
+
 def test_split_list_by_condition():
     items = ["-Iinclude", "-Llib", "-Wall"]