diff --git a/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in b/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in
index fd136a8385..00bda99d5b 100644
--- a/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in
+++ b/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in
@@ -137,7 +137,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.14.0"/>
+    <PackageReference Include="Google.Protobuf" Version="3.15.3"/>
   </ItemGroup>
 
   <!-- Need to add required runtime dependencies so Meta-Project will pull runtime Nuget(s) -->
diff --git a/ortools/java/pom-local.xml.in b/ortools/java/pom-local.xml.in
index aa6e9f2c43..9f14c6c815 100644
--- a/ortools/java/pom-local.xml.in
+++ b/ortools/java/pom-local.xml.in
@@ -70,7 +70,7 @@
   <dependency>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-java</artifactId>
-    <version>3.14.0</version>
+    <version>3.15.3</version>
   </dependency>
 </dependencies>
 
diff --git a/ortools/java/pom.xml.in b/ortools/java/pom.xml.in
index 34e50ec43e..633bcbe644 100644
--- a/ortools/java/pom.xml.in
+++ b/ortools/java/pom.xml.in
@@ -58,7 +58,7 @@
   <dependency>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-java</artifactId>
-    <version>3.14.0</version>
+    <version>3.15.3</version>
   </dependency>
   <dependency>
     <groupId>junit</groupId>
diff --git a/ortools/python/setup.py.in b/ortools/python/setup.py.in
index 02ac4d786e..eeaf2fe6d2 100644
--- a/ortools/python/setup.py.in
+++ b/ortools/python/setup.py.in
@@ -42,7 +42,7 @@ setup(
     version='@PROJECT_VERSION@',
     packages=find_packages(),
     install_requires=[
-        'protobuf >= 3.14.0',
+        'protobuf >= 3.15.3',
         'absl-py >= 0.11',
     ],
     package_data={