diff --git a/registry/IwyuFilter_registry.yaml b/registry/IwyuFilter_registry.yaml
new file mode 100644
index 000000000000..d7d93bdc6295
--- /dev/null
+++ b/registry/IwyuFilter_registry.yaml
@@ -0,0 +1,16 @@
+---
+assumeFilename: registry/source/registry.cxx
+blacklist:
+    registry/source/regimpl.hxx:
+    # Needed for correct linker visibility
+    - regapi.hxx
+    registry/source/reflwrit.cxx:
+    # OSL_BIGENDIAN is being checked
+    - osl/endian.h
+    # Needed for correct linker visibility
+    - registry/writer.h
+    registry/source/reflread.cxx:
+    # OSL_BIGENDIAN is being checked
+    - osl/endian.h
+    # Needed for correct linker visibility
+    - registry/typereg_reader.hxx
diff --git a/registry/inc/regapi.hxx b/registry/inc/regapi.hxx
index 35c4ddda35a9..ae5b7e119e48 100644
--- a/registry/inc/regapi.hxx
+++ b/registry/inc/regapi.hxx
@@ -20,7 +20,6 @@
 #ifndef INCLUDED_REGISTRY_INC_REGAPI_HXX
 #define INCLUDED_REGISTRY_INC_REGAPI_HXX
 
-#include <stddef.h>
 #include <rtl/ustring.h>
 #include <registry/regtype.h>
 #include <registry/regdllapi.h>
diff --git a/registry/source/keyimpl.hxx b/registry/source/keyimpl.hxx
index d5c6ada33395..a964866d68bd 100644
--- a/registry/source/keyimpl.hxx
+++ b/registry/source/keyimpl.hxx
@@ -20,7 +20,6 @@
 #ifndef INCLUDED_REGISTRY_SOURCE_KEYIMPL_HXX
 #define INCLUDED_REGISTRY_SOURCE_KEYIMPL_HXX
 
-#include <regapi.hxx>
 #include "regimpl.hxx"
 #include <rtl/ustring.hxx>
 
diff --git a/registry/source/reflcnst.hxx b/registry/source/reflcnst.hxx
index a0ee421d5089..2fff0ca7340e 100644
--- a/registry/source/reflcnst.hxx
+++ b/registry/source/reflcnst.hxx
@@ -20,8 +20,7 @@
 #ifndef INCLUDED_REGISTRY_SOURCE_REFLCNST_HXX
 #define INCLUDED_REGISTRY_SOURCE_REFLCNST_HXX
 
-#include <registry/refltype.hxx>
-#include <sal/macros.h>
+#include <registry/types.hxx>
 
 #include <string.h>
 
diff --git a/registry/source/reflread.cxx b/registry/source/reflread.cxx
index f090383c6199..b799e8b30ef2 100644
--- a/registry/source/reflread.cxx
+++ b/registry/source/reflread.cxx
@@ -24,7 +24,6 @@
 #include <new>
 #include <vector>
 
-#include <string.h>
 #include <sal/types.h>
 #include <osl/endian.h>
 #include <osl/diagnose.h>
diff --git a/registry/source/reflread.hxx b/registry/source/reflread.hxx
index 880b6bcaddc0..e35e3e03e346 100644
--- a/registry/source/reflread.hxx
+++ b/registry/source/reflread.hxx
@@ -21,7 +21,6 @@
 #define INCLUDED_REGISTRY_SOURCE_REFLREAD_HXX
 
 #include <registry/refltype.hxx>
-#include <registry/regtype.h>
 #include <rtl/ustring.hxx>
 
 /// Implememetation handle
diff --git a/registry/source/reflwrit.cxx b/registry/source/reflwrit.cxx
index 9c753cf9c444..e06f575a859c 100644
--- a/registry/source/reflwrit.cxx
+++ b/registry/source/reflwrit.cxx
@@ -22,13 +22,12 @@
 #include <memory>
 #include <algorithm>
 #include <sal/types.h>
-#include <sal/macros.h>
 #include <osl/endian.h>
-#include <rtl/alloc.h>
 #include <rtl/string.hxx>
 #include <rtl/ustring.hxx>
 
 #include "reflwrit.hxx"
+#include <registry/refltype.hxx>
 #include <registry/version.h>
 #include <registry/writer.h>
 
diff --git a/registry/source/reflwrit.hxx b/registry/source/reflwrit.hxx
index 39a703259f64..6ea4d0e3a925 100644
--- a/registry/source/reflwrit.hxx
+++ b/registry/source/reflwrit.hxx
@@ -20,10 +20,11 @@
 #ifndef INCLUDED_REGISTRY_SOURCE_REFLWRIT_HXX
 #define INCLUDED_REGISTRY_SOURCE_REFLWRIT_HXX
 
-#include <registry/refltype.hxx>
-#include <registry/regtype.h>
+#include <registry/types.hxx>
 #include <rtl/ustring.hxx>
 
+class RTConstValue;
+
 /// Implememetation handle
 typedef void* TypeWriterImpl;
 
diff --git a/registry/source/regimpl.cxx b/registry/source/regimpl.cxx
index 9f01788b0f4b..ea074732df12 100644
--- a/registry/source/regimpl.cxx
+++ b/registry/source/regimpl.cxx
@@ -21,6 +21,7 @@
 #include "regimpl.hxx"
 
 #include <memory>
+#include <set>
 #include <vector>
 #include <string.h>
 #include <stdio.h>
@@ -36,13 +37,11 @@
 #include <registry/reader.hxx>
 #include <registry/refltype.hxx>
 #include <registry/types.hxx>
-#include <registry/version.h>
 
 #include "reflcnst.hxx"
 #include "keyimpl.hxx"
 
 #include <osl/thread.h>
-#include <rtl/alloc.h>
 #include <rtl/ustring.hxx>
 #include <rtl/ustrbuf.hxx>
 #include <osl/file.hxx>
diff --git a/registry/source/regimpl.hxx b/registry/source/regimpl.hxx
index 928807bc6642..d8a77394f2ac 100644
--- a/registry/source/regimpl.hxx
+++ b/registry/source/regimpl.hxx
@@ -20,10 +20,10 @@
 #ifndef INCLUDED_REGISTRY_SOURCE_REGIMPL_HXX
 #define INCLUDED_REGISTRY_SOURCE_REGIMPL_HXX
 
-#include <set>
 #include <unordered_map>
 
 #include <regapi.hxx>
+#include <registry/regtype.h>
 #include <rtl/ustring.hxx>
 #include <osl/mutex.hxx>
 #include <store/store.hxx>
diff --git a/registry/source/registry.cxx b/registry/source/registry.cxx
index b183f634eb97..166354aa5d62 100644
--- a/registry/source/registry.cxx
+++ b/registry/source/registry.cxx
@@ -18,11 +18,8 @@
  */
 
 
-#include <regapi.hxx>
 #include <registry/registry.hxx>
 
-#include <osl/process.h>
-
 #include "keyimpl.hxx"
 #include "regimpl.hxx"
 #include "regkey.hxx"
@@ -31,12 +28,6 @@
 #include <io.h>
 #endif
 
-#include <string.h>
-#if defined(UNX)
-#include <stdlib.h>
-#include <unistd.h>
-#endif
-
 extern "C" {
 
 
diff --git a/registry/source/regkey.cxx b/registry/source/regkey.cxx
index 52bb9105ac92..b63bb5ccf1e1 100644
--- a/registry/source/regkey.cxx
+++ b/registry/source/regkey.cxx
@@ -20,8 +20,6 @@
 
 #include "regkey.hxx"
 
-#include <registry/registry.hxx>
-#include <rtl/alloc.h>
 #include <osl/diagnose.h>
 #include "regimpl.hxx"
 #include "keyimpl.hxx"
diff --git a/registry/tools/fileurl.cxx b/registry/tools/fileurl.cxx
index cabfb16e95da..8495b1fce226 100644
--- a/registry/tools/fileurl.cxx
+++ b/registry/tools/fileurl.cxx
@@ -20,7 +20,6 @@
 #include "fileurl.hxx"
 
 #include <rtl/ustring.hxx>
-#include <osl/diagnose.h>
 #include <osl/file.hxx>
 #include <osl/process.h>
 #include <osl/thread.h>
diff --git a/registry/tools/options.cxx b/registry/tools/options.cxx
index 0f929b4230aa..e9b9c23950bf 100644
--- a/registry/tools/options.cxx
+++ b/registry/tools/options.cxx
@@ -22,7 +22,6 @@
 #include <osl/diagnose.h>
 
 #include <stdio.h>
-#include <string.h>
 
 namespace registry
 {
diff --git a/registry/tools/options.hxx b/registry/tools/options.hxx
index 6b6264455037..236ad37a5eb2 100644
--- a/registry/tools/options.hxx
+++ b/registry/tools/options.hxx
@@ -23,8 +23,6 @@
 #include <string>
 #include <vector>
 
-#include <sal/types.h>
-
 namespace registry
 {
 namespace tools