diff --git a/src/SFML/Network/Packet.cpp b/src/SFML/Network/Packet.cpp
index e639c049a..210a7f6b2 100644
--- a/src/SFML/Network/Packet.cpp
+++ b/src/SFML/Network/Packet.cpp
@@ -33,6 +33,7 @@
 
 #include <array>
 
+#include <cassert>
 #include <cstring>
 #include <cwchar>
 
@@ -255,6 +256,8 @@ Packet& Packet::operator>>(double& data)
 ////////////////////////////////////////////////////////////
 Packet& Packet::operator>>(char* data)
 {
+    assert(data && "Packet::operator>> Data must not be null");
+
     // First extract string length
     std::uint32_t length = 0;
     *this >> length;
@@ -297,6 +300,8 @@ Packet& Packet::operator>>(std::string& data)
 ////////////////////////////////////////////////////////////
 Packet& Packet::operator>>(wchar_t* data)
 {
+    assert(data && "Packet::operator>> Data must not be null");
+
     // First extract string length
     std::uint32_t length = 0;
     *this >> length;
@@ -482,6 +487,8 @@ Packet& Packet::operator<<(double data)
 ////////////////////////////////////////////////////////////
 Packet& Packet::operator<<(const char* data)
 {
+    assert(data && "Packet::operator<< Data must not be null");
+
     // First insert string length
     const auto length = static_cast<std::uint32_t>(std::strlen(data));
     *this << length;
@@ -511,6 +518,8 @@ Packet& Packet::operator<<(const std::string& data)
 ////////////////////////////////////////////////////////////
 Packet& Packet::operator<<(const wchar_t* data)
 {
+    assert(data && "Packet::operator<< Data must not be null");
+
     // First insert string length
     const auto length = static_cast<std::uint32_t>(std::wcslen(data));
     *this << length;
diff --git a/src/SFML/Window/Context.cpp b/src/SFML/Window/Context.cpp
index ce41074ac..b3cd546ca 100644
--- a/src/SFML/Window/Context.cpp
+++ b/src/SFML/Window/Context.cpp
@@ -33,6 +33,8 @@
 #include <ostream>
 #include <utility>
 
+#include <cassert>
+
 
 namespace
 {
@@ -135,6 +137,7 @@ bool Context::isExtensionAvailable(std::string_view name)
 ////////////////////////////////////////////////////////////
 GlFunctionPointer Context::getFunction(const char* name)
 {
+    assert(name && "Context::getFunction Name must not be null");
     return priv::GlContext::getFunction(name);
 }