diff --git a/src/gravity/Default/gravity.h b/src/gravity/Default/gravity.h
index 755d4be527e4a81b2b4d2b3b829ea16a74ccc7c5..f9b67c96331e7572b0200093f0c32eee5d2391cd 100644
--- a/src/gravity/Default/gravity.h
+++ b/src/gravity/Default/gravity.h
@@ -17,6 +17,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  ******************************************************************************/
+#ifndef SWIFT_DEFAULT_GRAVITY_H
+#define SWIFT_DEFAULT_GRAVITY_H
 
 #include <float.h>
 #include "potentials.h"
@@ -151,3 +153,5 @@ __attribute__((always_inline)) INLINE static void external_gravity(
  */
 __attribute__((always_inline)) INLINE static void gravity_kick_extra(
     struct gpart* gp, float dt, float half_dt) {}
+
+#endif /* SWIFT_DEFAULT_GRAVITY_H */
diff --git a/src/gravity/Default/gravity_debug.h b/src/gravity/Default/gravity_debug.h
index 7cf375a1fdf7bccc4131dc415ab2d4acbbf2d3bc..c284f543b3be06297600c010e302423eb683adc9 100644
--- a/src/gravity/Default/gravity_debug.h
+++ b/src/gravity/Default/gravity_debug.h
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  ******************************************************************************/
+#ifndef SWIFT_DEFAULT_GRAVITY_DEBUG_H
+#define SWIFT_DEFAULT_GRAVITY_DEBUG_H
 
 __attribute__((always_inline)) INLINE static void gravity_debug_particle(
     const struct gpart* p) {
@@ -27,3 +29,5 @@ __attribute__((always_inline)) INLINE static void gravity_debug_particle(
       p->a_grav[0], p->a_grav[1], p->a_grav[2], p->mass, p->ti_begin,
       p->ti_end);
 }
+
+#endif /* SWIFT_DEFAULT_GRAVITY_DEBUG_H */
diff --git a/src/gravity/Default/gravity_iact.h b/src/gravity/Default/gravity_iact.h
index aa285ce3245aeac608aa022924a613a7a7b00375..7c7c5b9d244534ef3f6b5f509062019bfcd5f9fb 100644
--- a/src/gravity/Default/gravity_iact.h
+++ b/src/gravity/Default/gravity_iact.h
@@ -17,8 +17,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  ******************************************************************************/
-#ifndef SWIFT_RUNNER_IACT_GRAV_H
-#define SWIFT_RUNNER_IACT_GRAV_H
+#ifndef SWIFT_DEFAULT_GRAVITY_IACT_H
+#define SWIFT_DEFAULT_GRAVITY_IACT_H
 
 /* Includes. */
 #include "const.h"
@@ -188,4 +188,4 @@ __attribute__((always_inline)) INLINE static void runner_iact_grav_pm(
 #endif
 }
 
-#endif /* SWIFT_RUNNER_IACT_GRAV_H */
+#endif /* SWIFT_DEFAULT_GRAVITY_IACT_H */
diff --git a/src/gravity/Default/gravity_io.h b/src/gravity/Default/gravity_io.h
index e0fd15a91b6e20048f6844b03ea1dde40114d7ec..26eed8a0a680e13130dd257d8b31e6cd00392f6d 100644
--- a/src/gravity/Default/gravity_io.h
+++ b/src/gravity/Default/gravity_io.h
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  ******************************************************************************/
+#ifndef SWIFT_DEFAULT_GRAVITY_IO_H
+#define SWIFT_DEFAULT_GRAVITY_IO_H
 
 #include "io_properties.h"
 
@@ -68,3 +70,5 @@ void darkmatter_write_particles(struct gpart* gparts, struct io_props* list,
   list[4] = io_make_output_field("Acceleration", FLOAT, 3,
                                  UNIT_CONV_ACCELERATION, gparts, a_grav);
 }
+
+#endif /* SWIFT_DEFAULT_GRAVITY_IO_H */
diff --git a/src/gravity/Default/gravity_part.h b/src/gravity/Default/gravity_part.h
index 77e6543429993bea355c04dd28fcb5b04eee5519..1850ff0a1644d3593f78f150646eae8b2f074e1e 100644
--- a/src/gravity/Default/gravity_part.h
+++ b/src/gravity/Default/gravity_part.h
@@ -16,6 +16,9 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  ******************************************************************************/
+#ifndef SWIFT_DEFAULT_GRAVITY_PART_H
+#define SWIFT_DEFAULT_GRAVITY_PART_H
+
 /* Some standard headers. */
 #include <stdlib.h>
 
@@ -51,3 +54,5 @@ struct gpart {
   long long id_or_neg_offset;
 
 } __attribute__((aligned(gpart_align)));
+
+#endif /* SWIFT_DEFAULT_GRAVITY_PART_H */