diff --git a/Makefile b/Makefile
index 85f5eb307b..9e8c76eff2 100644
--- a/Makefile
+++ b/Makefile
@@ -131,7 +131,10 @@ ifneq (Windows,$(UNAME))
 endif
 
 ifneq ($(BUILD),shared)
-	BUILD = static
+	BUILD := static
+endif
+ifeq ($(DEBUG),1)
+	BUILD := debug-$(BUILD)
 endif
 
 ifeq (,$(TRAVIS_BUILD_DIR))
diff --git a/Readme.md b/Readme.md
index a8f7019feb..3eaa63a598 100644
--- a/Readme.md
+++ b/Readme.md
@@ -48,6 +48,12 @@ Since LibSass is a pure library, tests are run through the [SassSpec](https://gi
 
 To run tests against LibSass while developing, you can run `./script/spec`. This will clone SassC and Sass-Spec under the project folder and then run the Sass-Spec test suite. You may want to update the clones to ensure you have the latest version.
 
+### DEBUG builds
+
+Set the environment variable `DEBUG` to `1` to enable debug builds that can be debugged
+with `gdb`, `lldb` and others. E.g.: use `$ DEBUG=1 ./script/spec` to run the tests with
+a debug build.
+
 Library Usage
 -------------