diff --git a/Misc/NEWS.d/next/Build/2019-12-30-10-54-49.bpo-39162.go2bIN.rst b/Misc/NEWS.d/next/Build/2019-12-30-10-54-49.bpo-39162.go2bIN.rst
new file mode 100644
index 00000000000000..3521dd3005486b
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2019-12-30-10-54-49.bpo-39162.go2bIN.rst
@@ -0,0 +1 @@
+Fixed an issue where the macOS SDK path wouldn't be discovered by setup.py, meaning _tkinter failed to build on macOS 10.15.
\ No newline at end of file
diff --git a/setup.py b/setup.py
index 02f523c42d355f..216defe51f2959 100644
--- a/setup.py
+++ b/setup.py
@@ -1769,16 +1769,15 @@ def detect_tkinter_darwin(self):
         for F in framework_dirs:
             # both Tcl.framework and Tk.framework should be present
 
-
             for fw in 'Tcl', 'Tk':
                 if is_macosx_sdk_path(F):
-                    if not exists(join(sysroot, F[1:], fw + '.framework')):
-                        break
+                    framework_path = join(sysroot, F[1:])
                 else:
-                    if not exists(join(F, fw + '.framework')):
-                        break
+                    framework_path = F
+                if not exists(join(framework_path, fw + '.framework')):
+                    break
             else:
-                # ok, F is now directory with both frameworks. Continure
+                # ok, framework_path is now directory with both frameworks. Continue
                 # building
                 break
         else:
@@ -1791,11 +1790,10 @@ def detect_tkinter_darwin(self):
         # the -F option to gcc, which specifies a framework lookup path.
         #
         include_dirs = [
-            join(F, fw + '.framework', H)
+            join(framework_path, fw + '.framework', H)
             for fw in ('Tcl', 'Tk')
             for H in ('Headers', 'Versions/Current/PrivateHeaders')
         ]
-
         # For 8.4a2, the X11 headers are not included. Rather than include a
         # complicated search, this is a hard-coded path. It could bail out
         # if X11 libs are not found...