diff --git a/CMakeLists.txt b/CMakeLists.txt
index fc40235..6bc4d75 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,7 +11,7 @@ set(CMAKE_BUILD_TYPE Release)
 set(mstch_VERSION 0.2.3)
 
 if(NOT MSVC)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -O3")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wextra -O3")
 endif()
 
 add_subdirectory(src)
diff --git a/src/visitor/get_token.hpp b/src/visitor/get_token.hpp
index dd7ba70..1915569 100644
--- a/src/visitor/get_token.hpp
+++ b/src/visitor/get_token.hpp
@@ -15,7 +15,7 @@ class get_token: public boost::static_visitor<const mstch::node&> {
   }
 
   template<class T>
-  const mstch::node& operator()(const T& t) const {
+  const mstch::node& operator()(const T&) const {
     return node;
   }
 
diff --git a/src/visitor/has_token.hpp b/src/visitor/has_token.hpp
index 1d15443..81c9cd3 100644
--- a/src/visitor/has_token.hpp
+++ b/src/visitor/has_token.hpp
@@ -12,7 +12,7 @@ class has_token: public boost::static_visitor<bool> {
   }
 
   template<class T>
-  bool operator()(const T& t) const {
+  bool operator()(const T&) const {
     return token == ".";
   }
 
diff --git a/src/visitor/is_node_empty.hpp b/src/visitor/is_node_empty.hpp
index 8119d4c..a0ae432 100644
--- a/src/visitor/is_node_empty.hpp
+++ b/src/visitor/is_node_empty.hpp
@@ -9,11 +9,11 @@ namespace mstch {
 class is_node_empty: public boost::static_visitor<bool> {
  public:
   template<class T>
-  bool operator()(const T& t) const {
+  bool operator()(const T&) const {
     return false;
   }
 
-  bool operator()(const std::nullptr_t& nul) const {
+  bool operator()(const std::nullptr_t&) const {
     return true;
   }
 
diff --git a/src/visitor/render_node.hpp b/src/visitor/render_node.hpp
index aef8027..03e9a47 100644
--- a/src/visitor/render_node.hpp
+++ b/src/visitor/render_node.hpp
@@ -18,7 +18,7 @@ class render_node: public boost::static_visitor<std::string> {
   }
 
   template<class T>
-  std::string operator()(const T& t) const {
+  std::string operator()(const T&) const {
     return "";
   }
 
diff --git a/test/specs_lambdas.hpp b/test/specs_lambdas.hpp
index 87ebd5f..6ec0d59 100644
--- a/test/specs_lambdas.hpp
+++ b/test/specs_lambdas.hpp
@@ -20,7 +20,7 @@ std::map<std::string,mstch::node> specs_lambdas {
     {"Section - Multiple Calls", mstch::lambda{[](const std::string& txt) -> mstch::node {
       return "__" + txt + "__";
     }}},
-    {"Inverted Section", mstch::lambda{[](const std::string& txt) -> mstch::node {
+    {"Inverted Section", mstch::lambda{[](const std::string&) -> mstch::node {
       return false;
     }}}
 };
\ No newline at end of file