diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca44a339..b41897d3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+-   fixes a bug where specifying both relative and absolute paths would cause sqlfmt to crash ([#426](https://github.com/tconbeer/sqlfmt/issues/426) - thank you for the issue and fix, [@smcgivern](https://github.com/smcgivern)!)
+
 ## [0.18.1] - 2023-05-10
 
 -   fixes a bug when lexing `union distinct` tokens ([#417](https://github.com/tconbeer/sqlfmt/issues/417) - thank you, [@paschmaria](https://github.com/paschmaria)!)
diff --git a/src/sqlfmt/config.py b/src/sqlfmt/config.py
index bdeffcd1..e73e1a53 100644
--- a/src/sqlfmt/config.py
+++ b/src/sqlfmt/config.py
@@ -34,7 +34,7 @@ def _get_common_parents(files: List[Path]) -> List[Path]:
     assert files, "Must provide a list of paths"
     common_parents: Set[Path] = set()
     for p in files:
-        parents = set(p.parents)
+        parents = set(p.absolute().parents)
         if p.is_dir():
             parents.add(p)
         if not common_parents:
diff --git a/tests/unit_tests/test_config.py b/tests/unit_tests/test_config.py
index bb0ae2b9..8caabb41 100644
--- a/tests/unit_tests/test_config.py
+++ b/tests/unit_tests/test_config.py
@@ -1,3 +1,4 @@
+import os
 from pathlib import Path
 from typing import Any, List
 
@@ -63,6 +64,29 @@ def test_find_config_file_not_in_tree(
     assert config_path is None
 
 
+def test_find_config_file_relative_and_absolute(
+    tmp_path: Path, files_relpath: List[Path]
+) -> None:
+    # Only check the cases where we are providing more than one path
+    if len(files_relpath) == 1:
+        return
+
+    current_dir = os.getcwd()
+    copy_config_file_to_dst("valid_sqlfmt_config.toml", tmp_path)
+
+    try:
+        os.chdir(tmp_path)
+
+        files = [tmp_path / files_relpath[0], files_relpath[1]]
+        search_paths = _get_common_parents(files)
+        assert tmp_path in search_paths
+        config_path = _find_config_file(search_paths)
+        assert config_path
+        assert config_path == tmp_path / "pyproject.toml"
+    finally:
+        os.chdir(current_dir)
+
+
 def test_load_config_from_path(tmp_path: Path) -> None:
     copy_config_file_to_dst("valid_sqlfmt_config.toml", tmp_path)
     config = _load_config_from_path(tmp_path / "pyproject.toml")