diff --git a/lexilla/Lexilla.vcxproj b/lexilla/Lexilla.vcxproj
index 65017a17d..2a52ebed3 100644
--- a/lexilla/Lexilla.vcxproj
+++ b/lexilla/Lexilla.vcxproj
@@ -242,6 +242,7 @@
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
       <DebugInformationFormat>OldStyle</DebugInformationFormat>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -279,6 +280,7 @@
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
       <DebugInformationFormat>None</DebugInformationFormat>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -316,6 +318,7 @@
       <DebugInformationFormat>OldStyle</DebugInformationFormat>
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -349,6 +352,7 @@
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
       <DebugInformationFormat>OldStyle</DebugInformationFormat>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -385,6 +389,7 @@
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
       <DebugInformationFormat>None</DebugInformationFormat>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -421,6 +426,7 @@
       <EnableEnhancedInstructionSet />
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
diff --git a/scintilla/Scintilla.vcxproj b/scintilla/Scintilla.vcxproj
index 23e87a214..3e01643c4 100644
--- a/scintilla/Scintilla.vcxproj
+++ b/scintilla/Scintilla.vcxproj
@@ -187,6 +187,7 @@
       <MinimalRebuild>false</MinimalRebuild>
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <ProjectReference>
       <LinkLibraryDependencies>true</LinkLibraryDependencies>
@@ -215,6 +216,7 @@
       <MinimalRebuild>false</MinimalRebuild>
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Lib>
       <TargetMachine>MachineX64</TargetMachine>
@@ -250,6 +252,7 @@
       <MinimalRebuild>false</MinimalRebuild>
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <ProjectReference>
       <LinkLibraryDependencies>true</LinkLibraryDependencies>
@@ -282,6 +285,7 @@
       <IntrinsicFunctions>false</IntrinsicFunctions>
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <ProjectReference>
       <LinkLibraryDependencies>true</LinkLibraryDependencies>
@@ -316,6 +320,7 @@
       <MinimalRebuild>false</MinimalRebuild>
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Lib>
       <TargetMachine>
@@ -346,6 +351,7 @@
       <EnableEnhancedInstructionSet />
       <TreatWarningAsError>true</TreatWarningAsError>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Lib>
       <TargetMachine>MachineX64</TargetMachine>