diff --git a/src/api/encoding.cc b/src/api/encoding.cc
index 21d327509727..fa872f8b76cd 100644
--- a/src/api/encoding.cc
+++ b/src/api/encoding.cc
@@ -1,5 +1,4 @@
 #include "node.h"
-#include "env-inl.h"
 #include "string_bytes.h"
 #include "util-inl.h"
 #include "v8.h"
diff --git a/src/api/utils.cc b/src/api/utils.cc
index da7281a68f3b..f07f9bea234b 100644
--- a/src/api/utils.cc
+++ b/src/api/utils.cc
@@ -1,6 +1,4 @@
 #include "node.h"
-#include "node_internals.h"
-#include "util-inl.h"
 
 #include <csignal>
 
diff --git a/src/async_wrap.cc b/src/async_wrap.cc
index 8410dd2e0d8c..58d89225e0e5 100644
--- a/src/async_wrap.cc
+++ b/src/async_wrap.cc
@@ -27,7 +27,6 @@
 #include "util-inl.h"
 
 #include "v8.h"
-#include "v8-profiler.h"
 
 using v8::Context;
 using v8::DontDelete;
diff --git a/src/connect_wrap.cc b/src/connect_wrap.cc
index dacdf72da7c4..e1d34c11a70b 100644
--- a/src/connect_wrap.cc
+++ b/src/connect_wrap.cc
@@ -1,14 +1,12 @@
 #include "connect_wrap.h"
-
-#include "env-inl.h"
 #include "req_wrap-inl.h"
-#include "util-inl.h"
 
 namespace node {
 
 using v8::Local;
 using v8::Object;
 
+class Environment;
 
 ConnectWrap::ConnectWrap(Environment* env,
     Local<Object> req_wrap_obj,
diff --git a/src/connect_wrap.h b/src/connect_wrap.h
index 88221b774686..eaa533025759 100644
--- a/src/connect_wrap.h
+++ b/src/connect_wrap.h
@@ -3,10 +3,8 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "env.h"
 #include "req_wrap-inl.h"
 #include "async_wrap.h"
-#include "v8.h"
 
 namespace node {
 
diff --git a/src/connection_wrap.h b/src/connection_wrap.h
index db74dc5df4aa..e91b2ab35b6d 100644
--- a/src/connection_wrap.h
+++ b/src/connection_wrap.h
@@ -4,7 +4,6 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "stream_wrap.h"
-#include "v8.h"
 
 namespace node {
 
diff --git a/src/debug_utils.cc b/src/debug_utils.cc
index a55936f4e79c..4e52feb69d90 100644
--- a/src/debug_utils.cc
+++ b/src/debug_utils.cc
@@ -1,6 +1,5 @@
 #include "debug_utils.h"
 #include "env-inl.h"
-#include "util-inl.h"
 
 #ifdef __POSIX__
 #if defined(__linux__)
diff --git a/src/env.cc b/src/env.cc
index 5f9a6acb461f..62b8b59f4f32 100644
--- a/src/env.cc
+++ b/src/env.cc
@@ -7,7 +7,6 @@
 #include "node_errors.h"
 #include "node_file.h"
 #include "node_internals.h"
-#include "node_native_module.h"
 #include "node_options-inl.h"
 #include "node_process.h"
 #include "node_v8_platform-inl.h"
diff --git a/src/fs_event_wrap.cc b/src/fs_event_wrap.cc
index 5033f027b1f2..8a75f0557c4b 100644
--- a/src/fs_event_wrap.cc
+++ b/src/fs_event_wrap.cc
@@ -21,7 +21,6 @@
 
 #include "async_wrap-inl.h"
 #include "env-inl.h"
-#include "util-inl.h"
 #include "node.h"
 #include "handle_wrap.h"
 #include "string_bytes.h"
diff --git a/src/handle_wrap.cc b/src/handle_wrap.cc
index 198b0456e757..f5d622fc255c 100644
--- a/src/handle_wrap.cc
+++ b/src/handle_wrap.cc
@@ -23,7 +23,6 @@
 #include "async_wrap-inl.h"
 #include "env-inl.h"
 #include "util-inl.h"
-#include "node.h"
 
 namespace node {
 
diff --git a/src/js_stream.cc b/src/js_stream.cc
index 23bdb9b48925..a67fd37dbdb2 100644
--- a/src/js_stream.cc
+++ b/src/js_stream.cc
@@ -2,7 +2,6 @@
 
 #include "async_wrap.h"
 #include "env-inl.h"
-#include "node_buffer.h"
 #include "node_errors.h"
 #include "stream_base-inl.h"
 #include "util-inl.h"
diff --git a/src/js_stream.h b/src/js_stream.h
index 460ac23bc98b..d96b3d0062dc 100644
--- a/src/js_stream.h
+++ b/src/js_stream.h
@@ -5,7 +5,6 @@
 
 #include "async_wrap.h"
 #include "stream_base.h"
-#include "v8.h"
 
 namespace node {
 
diff --git a/src/module_wrap.h b/src/module_wrap.h
index ef20d255e916..bee4000d1680 100644
--- a/src/module_wrap.h
+++ b/src/module_wrap.h
@@ -6,10 +6,12 @@
 #include <unordered_map>
 #include <string>
 #include <vector>
-#include "node_url.h"
-#include "base_object-inl.h"
+#include "base_object.h"
 
 namespace node {
+
+class Environment;
+
 namespace loader {
 
 enum ScriptType : int {
diff --git a/src/node_binding.h b/src/node_binding.h
index dd94fab36a0e..42f3c5b8d008 100644
--- a/src/node_binding.h
+++ b/src/node_binding.h
@@ -10,9 +10,6 @@
 #include "node.h"
 #define NAPI_EXPERIMENTAL
 #include "node_api.h"
-#include "util.h"
-#include "uv.h"
-#include "v8.h"
 
 enum {
   NM_F_BUILTIN = 1 << 0,  // Unused.
diff --git a/src/node_buffer.cc b/src/node_buffer.cc
index d87d38334add..8641270eaecf 100644
--- a/src/node_buffer.cc
+++ b/src/node_buffer.cc
@@ -28,7 +28,6 @@
 #include "string_bytes.h"
 #include "string_search.h"
 #include "util-inl.h"
-#include "v8-profiler.h"
 #include "v8.h"
 
 #include <cstring>
diff --git a/src/node_errors.h b/src/node_errors.h
index f6fca6c690a1..6080aa93dba4 100644
--- a/src/node_errors.h
+++ b/src/node_errors.h
@@ -3,8 +3,6 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "node.h"
-#include "util.h"
 #include "env.h"
 #include "v8.h"
 
diff --git a/src/node_watchdog.h b/src/node_watchdog.h
index d26f022d8487..0fc133a96c4a 100644
--- a/src/node_watchdog.h
+++ b/src/node_watchdog.h
@@ -24,7 +24,6 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "v8.h"
 #include "uv.h"
 #include "node_mutex.h"
 #include <vector>
diff --git a/src/stream_wrap.h b/src/stream_wrap.h
index 37f5af460661..816f557ee6cb 100644
--- a/src/stream_wrap.h
+++ b/src/stream_wrap.h
@@ -26,7 +26,6 @@
 
 #include "stream_base.h"
 #include "handle_wrap.h"
-#include "string_bytes.h"
 #include "v8.h"
 
 namespace node {
diff --git a/src/string_bytes.h b/src/string_bytes.h
index 6ffdc47db799..5ef05fc48cd5 100644
--- a/src/string_bytes.h
+++ b/src/string_bytes.h
@@ -27,7 +27,7 @@
 // Decodes a v8::Local<v8::String> or Buffer to a raw char*
 
 #include "v8.h"
-#include "env.h"
+#include "env-inl.h"
 
 namespace node {
 
diff --git a/src/string_decoder-inl.h b/src/string_decoder-inl.h
index 8a04211906f7..e7c0abb51546 100644
--- a/src/string_decoder-inl.h
+++ b/src/string_decoder-inl.h
@@ -4,7 +4,6 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "string_decoder.h"
-#include "util.h"
 
 namespace node {
 
diff --git a/src/tracing/agent.h b/src/tracing/agent.h
index a129f954d7bf..7ee1b417c6ff 100644
--- a/src/tracing/agent.h
+++ b/src/tracing/agent.h
@@ -3,7 +3,6 @@
 
 #include "libplatform/v8-tracing.h"
 #include "uv.h"
-#include "v8.h"
 #include "util.h"
 #include "node_mutex.h"
 
@@ -12,6 +11,11 @@
 #include <string>
 #include <unordered_map>
 
+namespace v8 {
+class ConvertableToTraceFormat;
+class TracingController;
+}  // namespace v8
+
 namespace node {
 namespace tracing {
 
diff --git a/src/udp_wrap.h b/src/udp_wrap.h
index 6375ac2d1b8c..2026dd1dee1e 100644
--- a/src/udp_wrap.h
+++ b/src/udp_wrap.h
@@ -24,7 +24,6 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "async_wrap.h"
 #include "handle_wrap.h"
 #include "uv.h"
 #include "v8.h"