diff --git a/README.md b/README.md
index 01d2784..f2db21c 100644
--- a/README.md
+++ b/README.md
@@ -77,8 +77,9 @@ can install it manually using either:
    - Use `:lua require('dap-python').test_method()` to debug the closest method above the cursor.
 
    Supported test frameworks are `unittest`, `pytest` and `django`. By default it
-   tries to detect the runner by probing for `pytest.ini` and `manage.py`, if
-   neither are present it defaults to `unittest`.
+   tries to detect the runner by probing for presence of `pytest.ini` or
+   `manage.py`, or for a `tool.pytest` directive inside `pyproject.toml`, if
+   none are present it defaults to `unittest`.
 
    To configure a different runner, change the `test_runner` variable. For
    example, to configure `pytest` set the test runner like this in your
diff --git a/doc/dap-python.txt b/doc/dap-python.txt
index b9ce360..c7afd76 100644
--- a/doc/dap-python.txt
+++ b/doc/dap-python.txt
@@ -3,8 +3,8 @@ Python extension for nvim-dap                                       *dap-python*
 
 M.test_runner                                           *dap-python.test_runner*
      Test runner to use by default.
-     The default value is dynamic and depends on `pytest.ini` or `manage.py` markers.
-     If neither is found "unittest" is used. See |dap-python.test_runners|
+     The default value is dynamic and depends on `pytest.ini`, `manage.py` or `pyproject.toml` markers.
+     If none are found "unittest" is used. See |dap-python.test_runners|
      Override this to set a different runner:
      ```
      require('dap-python').test_runner = "pytest"
diff --git a/lua/dap-python.lua b/lua/dap-python.lua
index 4873b15..9560792 100644
--- a/lua/dap-python.lua
+++ b/lua/dap-python.lua
@@ -22,28 +22,6 @@ M.test_runner = nil
 M.resolve_python = nil
 
 
-local function default_runner()
-  if uv.fs_stat('pytest.ini') then
-    return 'pytest'
-  elseif uv.fs_stat('manage.py') then
-    return 'django'
-  elseif uv.fs_stat("pyproject.toml") then
-    local f = io.open("pyproject.toml")
-    if f then
-      for line in f:lines() do
-        if line:find("%[tool.pytest") then
-          f:close()
-          return "pytest"
-        end
-      end
-      f:close()
-    end
-    return 'unittest'
-  else
-    return 'unittest'
-  end
-end
-
 --- Table to register test runners.
 --- Built-in are test runners for unittest, pytest and django.
 --- The key is the test runner name, the value a function to generate the
@@ -88,6 +66,30 @@ local function roots()
 end
 
 
+local function default_runner()
+  for root in roots() do
+    if uv.fs_stat(root .. "/pytest.ini") then
+      return "pytest"
+    elseif uv.fs_stat(root .. "/manage.py") then
+      return "django"
+    elseif uv.fs_stat(root .. "/pyproject.toml") then
+      local f = io.open(root .. "/pyproject.toml")
+      if f then
+        for line in f:lines() do
+          if line:find("%[tool.pytest") then
+            f:close()
+            return "pytest"
+          end
+        end
+        f:close()
+      end
+    end
+  end
+
+  return "unittest"
+end
+
+
 local get_python_path = function()
   local venv_path = os.getenv('VIRTUAL_ENV')
   if venv_path then