diff --git a/src/bindgen/bindings.rs b/src/bindgen/bindings.rs
index ee05761..495d128 100644
--- a/src/bindgen/bindings.rs
+++ b/src/bindgen/bindings.rs
@@ -126,6 +126,10 @@ impl Bindings {
             self.write_headers(&mut out);
         }
 
+        if self.config.language == Language::Cxx {
+            self.open_namespaces(&mut out);
+        }
+
         for constant in &self.constants {
             if constant.ty.is_primitive_or_ptr_primitive() {
                 out.new_line_if_not_start();
@@ -134,9 +138,6 @@ impl Bindings {
             }
         }
 
-        if self.config.language == Language::Cxx {
-            self.open_namespaces(&mut out);
-        }
         for item in &self.items {
             if item
                 .deref()
diff --git a/tests/expectations/both/namespace_constant.c b/tests/expectations/both/namespace_constant.c
new file mode 100644
index 0000000..90538df
--- /dev/null
+++ b/tests/expectations/both/namespace_constant.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define FOO 10
+
+#define ZOM 3.14
+
+typedef struct Foo {
+  int32_t x[FOO];
+} Foo;
+
+void root(Foo x);
diff --git a/tests/expectations/both/namespaces_constant.c b/tests/expectations/both/namespaces_constant.c
new file mode 100644
index 0000000..90538df
--- /dev/null
+++ b/tests/expectations/both/namespaces_constant.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define FOO 10
+
+#define ZOM 3.14
+
+typedef struct Foo {
+  int32_t x[FOO];
+} Foo;
+
+void root(Foo x);
diff --git a/tests/expectations/namespace_constant.c b/tests/expectations/namespace_constant.c
new file mode 100644
index 0000000..5858773
--- /dev/null
+++ b/tests/expectations/namespace_constant.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define FOO 10
+
+#define ZOM 3.14
+
+typedef struct {
+  int32_t x[FOO];
+} Foo;
+
+void root(Foo x);
diff --git a/tests/expectations/namespace_constant.cpp b/tests/expectations/namespace_constant.cpp
new file mode 100644
index 0000000..df5e4e0
--- /dev/null
+++ b/tests/expectations/namespace_constant.cpp
@@ -0,0 +1,20 @@
+#include <cstdint>
+#include <cstdlib>
+
+namespace constants {
+
+static const int32_t FOO = 10;
+
+static const float ZOM = 3.14;
+
+struct Foo {
+  int32_t x[FOO];
+};
+
+extern "C" {
+
+void root(Foo x);
+
+} // extern "C"
+
+} // namespace constants
diff --git a/tests/expectations/namespaces_constant.c b/tests/expectations/namespaces_constant.c
new file mode 100644
index 0000000..5858773
--- /dev/null
+++ b/tests/expectations/namespaces_constant.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define FOO 10
+
+#define ZOM 3.14
+
+typedef struct {
+  int32_t x[FOO];
+} Foo;
+
+void root(Foo x);
diff --git a/tests/expectations/namespaces_constant.cpp b/tests/expectations/namespaces_constant.cpp
new file mode 100644
index 0000000..5cdf532
--- /dev/null
+++ b/tests/expectations/namespaces_constant.cpp
@@ -0,0 +1,22 @@
+#include <cstdint>
+#include <cstdlib>
+
+namespace constants {
+namespace test {
+
+static const int32_t FOO = 10;
+
+static const float ZOM = 3.14;
+
+struct Foo {
+  int32_t x[FOO];
+};
+
+extern "C" {
+
+void root(Foo x);
+
+} // extern "C"
+
+} // namespace test
+} // namespace constants
diff --git a/tests/expectations/tag/namespace_constant.c b/tests/expectations/tag/namespace_constant.c
new file mode 100644
index 0000000..8def269
--- /dev/null
+++ b/tests/expectations/tag/namespace_constant.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define FOO 10
+
+#define ZOM 3.14
+
+struct Foo {
+  int32_t x[FOO];
+};
+
+void root(struct Foo x);
diff --git a/tests/expectations/tag/namespaces_constant.c b/tests/expectations/tag/namespaces_constant.c
new file mode 100644
index 0000000..8def269
--- /dev/null
+++ b/tests/expectations/tag/namespaces_constant.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define FOO 10
+
+#define ZOM 3.14
+
+struct Foo {
+  int32_t x[FOO];
+};
+
+void root(struct Foo x);
diff --git a/tests/rust/namespace_constant.rs b/tests/rust/namespace_constant.rs
new file mode 100644
index 0000000..ee67081
--- /dev/null
+++ b/tests/rust/namespace_constant.rs
@@ -0,0 +1,11 @@
+const FOO: i32 = 10;
+const BAR: &'static str = "hello world";
+const ZOM: f32 = 3.14;
+
+#[repr(C)]
+struct Foo {
+    x: [i32; FOO],
+}
+
+#[no_mangle]
+pub extern "C" fn root(x: Foo) { }
diff --git a/tests/rust/namespace_constant.toml b/tests/rust/namespace_constant.toml
new file mode 100644
index 0000000..1b9d94e
--- /dev/null
+++ b/tests/rust/namespace_constant.toml
@@ -0,0 +1 @@
+namespace = "constants"
diff --git a/tests/rust/namespaces_constant.rs b/tests/rust/namespaces_constant.rs
new file mode 100644
index 0000000..ee67081
--- /dev/null
+++ b/tests/rust/namespaces_constant.rs
@@ -0,0 +1,11 @@
+const FOO: i32 = 10;
+const BAR: &'static str = "hello world";
+const ZOM: f32 = 3.14;
+
+#[repr(C)]
+struct Foo {
+    x: [i32; FOO],
+}
+
+#[no_mangle]
+pub extern "C" fn root(x: Foo) { }
diff --git a/tests/rust/namespaces_constant.toml b/tests/rust/namespaces_constant.toml
new file mode 100644
index 0000000..7601ad3
--- /dev/null
+++ b/tests/rust/namespaces_constant.toml
@@ -0,0 +1 @@
+namespaces = ["constants", "test"]