diff --git a/stacktrace.go b/stacktrace.go
index 324c4bc..b12baa2 100644
--- a/stacktrace.go
+++ b/stacktrace.go
@@ -247,3 +247,8 @@ func (st *stacktrace) ExitCode() int {
 	}
 	return int(st.code)
 }
+
+// Unwrap returns the cause of st.
+func (st *stacktrace) Unwrap() error {
+	return st.cause
+}
diff --git a/stacktrace_test.go b/stacktrace_test.go
index c1276f2..ce6933d 100644
--- a/stacktrace_test.go
+++ b/stacktrace_test.go
@@ -98,3 +98,8 @@ func TestPropagateNil(t *testing.T) {
 
 	assert.Equal(t, stacktrace.NoCode, stacktrace.GetCode(err))
 }
+
+func TestUnwrap(t *testing.T) {
+	err := errors.New("cause")
+	assert.Equal(t, err, unwrap(stacktrace.Propagate(err, "propagated")))
+}
diff --git a/unwrap_1_13_test.go b/unwrap_1_13_test.go
new file mode 100644
index 0000000..82b412a
--- /dev/null
+++ b/unwrap_1_13_test.go
@@ -0,0 +1,9 @@
+// +build go1.13
+
+package stacktrace_test
+
+import "errors"
+
+func unwrap(err error) error {
+	return errors.Unwrap(err)
+}
diff --git a/unwrap_test.go b/unwrap_test.go
new file mode 100644
index 0000000..cef3dae
--- /dev/null
+++ b/unwrap_test.go
@@ -0,0 +1,11 @@
+// +build !go1.13
+
+package stacktrace_test
+
+func unwrap(err error) error {
+	t, ok := err.(interface{ Unwrap() error })
+	if !ok {
+		return nil
+	}
+	return t.Unwrap()
+}