diff --git a/src/threading/ReactionHandle.cpp b/src/threading/ReactionHandle.cpp
index 45db51f6c..f2c43b2d1 100644
--- a/src/threading/ReactionHandle.cpp
+++ b/src/threading/ReactionHandle.cpp
@@ -22,6 +22,10 @@
 
 #include "ReactionHandle.hpp"
 
+#include <memory>
+
+#include "Reaction.hpp"
+
 namespace NUClear {
 namespace threading {
 
diff --git a/src/threading/scheduler/CombinedLock.cpp b/src/threading/scheduler/CombinedLock.cpp
index c1dfb7052..df40a2b94 100644
--- a/src/threading/scheduler/CombinedLock.cpp
+++ b/src/threading/scheduler/CombinedLock.cpp
@@ -21,6 +21,10 @@
  */
 #include "CombinedLock.hpp"
 
+#include <memory>
+#include <thread>
+#include <utility>
+
 namespace NUClear {
 namespace threading {
     namespace scheduler {
diff --git a/src/threading/scheduler/CountingLock.cpp b/src/threading/scheduler/CountingLock.cpp
index 77535d40e..1069eaa95 100644
--- a/src/threading/scheduler/CountingLock.cpp
+++ b/src/threading/scheduler/CountingLock.cpp
@@ -22,7 +22,6 @@
 #include "CountingLock.hpp"
 
 #include <atomic>
-#include <utility>
 
 namespace NUClear {
 namespace threading {
diff --git a/src/util/FileDescriptor.cpp b/src/util/FileDescriptor.cpp
index a494d7a35..2c0e691bf 100644
--- a/src/util/FileDescriptor.cpp
+++ b/src/util/FileDescriptor.cpp
@@ -22,6 +22,7 @@
 
 #include "FileDescriptor.hpp"
 
+#include <functional>
 #include <utility>
 
 #include "platform.hpp"
diff --git a/src/util/Sleeper.cpp b/src/util/Sleeper.cpp
index faa9e70c0..b8bda6e94 100644
--- a/src/util/Sleeper.cpp
+++ b/src/util/Sleeper.cpp
@@ -22,7 +22,6 @@
 
 #include "Sleeper.hpp"
 
-#include <array>
 #include <chrono>
 
 #if defined(_WIN32)
@@ -63,7 +62,6 @@ namespace util {
 #else
 
     #include <cerrno>
-    #include <cstdint>
     #include <ctime>
 
 namespace NUClear {
diff --git a/src/util/main_thread_id.cpp b/src/util/main_thread_id.cpp
index f0b845f30..41f1e3f88 100644
--- a/src/util/main_thread_id.cpp
+++ b/src/util/main_thread_id.cpp
@@ -22,6 +22,8 @@
 
 #include "main_thread_id.hpp"
 
+#include <thread>
+
 namespace NUClear {
 namespace util {
 
diff --git a/src/util/network/resolve.cpp b/src/util/network/resolve.cpp
index 23c40bf06..98034614c 100644
--- a/src/util/network/resolve.cpp
+++ b/src/util/network/resolve.cpp
@@ -22,12 +22,15 @@
 
 #include "resolve.hpp"
 
+#include <cstdint>
 #include <cstring>
 #include <memory>
 #include <stdexcept>
+#include <string>
 #include <system_error>
 
 #include "../platform.hpp"
+#include "sock_t.hpp"
 
 namespace NUClear {
 namespace util {
diff --git a/src/util/network/sock_t.hpp b/src/util/network/sock_t.hpp
index 7a16311f5..0fd4c5506 100644
--- a/src/util/network/sock_t.hpp
+++ b/src/util/network/sock_t.hpp
@@ -40,7 +40,7 @@ namespace util {
                 sockaddr_in6 ipv6;
             };
 
-            inline socklen_t size() const {
+            socklen_t size() const {
                 switch (sock.sa_family) {
                     case AF_INET: return sizeof(sockaddr_in);
                     case AF_INET6: return sizeof(sockaddr_in6);
@@ -50,7 +50,7 @@ namespace util {
                 }
             }
 
-            inline std::pair<std::string, in_port_t> address() const {
+            std::pair<std::string, in_port_t> address() const {
                 std::array<char, std::max(INET_ADDRSTRLEN, INET6_ADDRSTRLEN)> c = {0};
                 switch (sock.sa_family) {
                     case AF_INET:
diff --git a/src/util/serialise/xxhash.cpp b/src/util/serialise/xxhash.cpp
index 3a87ca7a3..c0a1dbd81 100644
--- a/src/util/serialise/xxhash.cpp
+++ b/src/util/serialise/xxhash.cpp
@@ -22,6 +22,7 @@
 
 #include "xxhash.hpp"
 
+#include <cstdint>
 #include <type_traits>
 
 namespace NUClear {