diff --git a/i18npool/inc/localedata.hxx b/i18npool/inc/localedata.hxx
index 06cf68fa7fdf..cb1ef9ea9769 100644
--- a/i18npool/inc/localedata.hxx
+++ b/i18npool/inc/localedata.hxx
@@ -39,12 +39,6 @@
 
 namespace com::sun::star::beans { struct PropertyValue; }
 namespace com::sun::star::container { class XIndexAccess; }
-namespace com::sun::star::i18n { struct Currency; }
-namespace com::sun::star::i18n { struct Currency2; }
-namespace com::sun::star::i18n { struct FormatElement; }
-namespace com::sun::star::lang { struct Locale; }
-
-struct LocaleDataLookupTableItem;
 
 namespace i18npool {
 
diff --git a/i18npool/inc/ordinalsuffix.hxx b/i18npool/inc/ordinalsuffix.hxx
index 39342359fc06..c53429d28237 100644
--- a/i18npool/inc/ordinalsuffix.hxx
+++ b/i18npool/inc/ordinalsuffix.hxx
@@ -23,8 +23,6 @@
 #include <cppuhelper/implbase.hxx>
 #include <com/sun/star/lang/XServiceInfo.hpp>
 
-namespace com::sun::star::lang { struct Locale; }
-
 namespace i18npool {
 
 class OrdinalSuffixService final : public cppu::WeakImplHelper
diff --git a/idl/inc/basobj.hxx b/idl/inc/basobj.hxx
index c7d8b77f1466..d9630dc0957a 100644
--- a/idl/inc/basobj.hxx
+++ b/idl/inc/basobj.hxx
@@ -23,6 +23,7 @@
 #include "bastype.hxx"
 #include <vector>
 
+class SvStream;
 class SvTokenStream;
 class SvIdlDataBase;
 
diff --git a/idl/inc/bastype.hxx b/idl/inc/bastype.hxx
index ff4938764c6e..6187c87072dc 100644
--- a/idl/inc/bastype.hxx
+++ b/idl/inc/bastype.hxx
@@ -24,7 +24,6 @@
 
 class SvStringHashEntry;
 class SvIdlDataBase;
-class SvStream;
 class SvTokenStream;
 
 class SvBOOL
diff --git a/idl/inc/parser.hxx b/idl/inc/parser.hxx
index a9a0b66c6839..891a8d421507 100644
--- a/idl/inc/parser.hxx
+++ b/idl/inc/parser.hxx
@@ -25,9 +25,7 @@
 class SvTokenStream;
 class SvIdlDataBase;
 class SvMetaModule;
-class SvMetaTypeEnum;
 class SvStringHashEntry;
-class SvMetaType;
 class SvMetaClass;
 class SvBOOL;