diff --git a/man/NetworkManager.conf.xml b/man/NetworkManager.conf.xml
index 944c4ab603..0dc1b700d9 100644
--- a/man/NetworkManager.conf.xml
+++ b/man/NetworkManager.conf.xml
@@ -655,7 +655,7 @@ ipv6.ip6-privacy=0
         </varlistentry>
         <varlistentry>
           <term><varname>ethernet.mtu</varname></term>
-          <listitem><para>If configured explicitly to 0, the MTU is not reconfigured during device activation unless it is required due to IPv6 constraints. If left unspecified, a DHCP/IPv6 SLAAC provided value is used or a default of 1500.</para></listitem>
+          <listitem><para>If configured explicitly to 0, the MTU is not reconfigured during device activation unless it is required due to IPv6 constraints. If left unspecified, a DHCP/IPv6 SLAAC provided value is used or the MTU is not reconfigured during activation.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><varname>ethernet.wake-on-lan</varname></term>
diff --git a/src/devices/nm-device-infiniband.c b/src/devices/nm-device-infiniband.c
index f7875d0992..7e04127035 100644
--- a/src/devices/nm-device-infiniband.c
+++ b/src/devices/nm-device-infiniband.c
@@ -139,7 +139,7 @@ get_configured_mtu (NMDevice *device, gboolean *out_is_user_config)
 		}
 	}
 	*out_is_user_config = (mtu != 0);
-	return mtu ?: NM_DEVICE_DEFAULT_MTU_INFINIBAND;
+	return mtu;
 }
 
 static gboolean
diff --git a/src/devices/nm-device-ip-tunnel.c b/src/devices/nm-device-ip-tunnel.c
index 53b7cf4e5f..2f505ef4cf 100644
--- a/src/devices/nm-device-ip-tunnel.c
+++ b/src/devices/nm-device-ip-tunnel.c
@@ -767,7 +767,7 @@ get_configured_mtu (NMDevice *self, gboolean *out_is_user_config)
 		}
 	}
 	*out_is_user_config = (mtu != 0);
-	return mtu ?: NM_DEVICE_DEFAULT_MTU_WIRED;
+	return mtu;
 }
 
 static NMDeviceCapabilities
diff --git a/src/devices/nm-device-private.h b/src/devices/nm-device-private.h
index 1081580c48..05cb3f7d84 100644
--- a/src/devices/nm-device-private.h
+++ b/src/devices/nm-device-private.h
@@ -112,10 +112,6 @@ gboolean nm_device_ipv6_sysctl_set (NMDevice *self, const char *property, const
 
 /*****************************************************************************/
 
-#define NM_DEVICE_DEFAULT_MTU_WIRED          ((guint32) 1500)
-#define NM_DEVICE_DEFAULT_MTU_WIRELESS       ((guint32) 1500)
-#define NM_DEVICE_DEFAULT_MTU_INFINIBAND     ((guint32) 0)
-
 gint64 nm_device_get_configured_mtu_from_connection_default (NMDevice *self,
                                                              const char *property_name);
 
diff --git a/src/devices/nm-device-vlan.c b/src/devices/nm-device-vlan.c
index 06db644656..a74da8f229 100644
--- a/src/devices/nm-device-vlan.c
+++ b/src/devices/nm-device-vlan.c
@@ -586,7 +586,7 @@ get_configured_mtu (NMDevice *self, gboolean *out_is_user_config)
 	if (ifindex > 0)
 		mtu = nm_platform_link_get_mtu (nm_device_get_platform (NM_DEVICE (self)), ifindex);
 
-	return mtu ?: NM_DEVICE_DEFAULT_MTU_WIRED;
+	return mtu;
 }
 
 /*****************************************************************************/
diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 25b1184740..d7635dcfac 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -7094,7 +7094,7 @@ nm_device_get_configured_mtu_for_wired (NMDevice *self, gboolean *out_is_user_co
 	}
 
 	*out_is_user_config = FALSE;
-	return NM_DEVICE_DEFAULT_MTU_WIRED;
+	return 0;
 }
 
 /*****************************************************************************/
diff --git a/src/devices/wifi/nm-device-wifi.c b/src/devices/wifi/nm-device-wifi.c
index 633bcd6aae..9638a40c26 100644
--- a/src/devices/wifi/nm-device-wifi.c
+++ b/src/devices/wifi/nm-device-wifi.c
@@ -2937,7 +2937,7 @@ get_configured_mtu (NMDevice *device, gboolean *out_is_user_config)
 		}
 	}
 	*out_is_user_config = (mtu != 0);
-	return mtu ?: NM_DEVICE_DEFAULT_MTU_WIRELESS;
+	return mtu;
 }
 
 static gboolean