diff --git a/src/plugins/projectexplorer/environment.cpp b/src/plugins/projectexplorer/environment.cpp
index 434cc99afb96d65f65b78cb79500bc879968395d..154cb7f311a1c03000db12d50240e00a52804566 100644
--- a/src/plugins/projectexplorer/environment.cpp
+++ b/src/plugins/projectexplorer/environment.cpp
@@ -288,12 +288,12 @@ void Environment::modify(const QList<EnvironmentItem> & list)
     *this = resultEnvironment;
 }
 
-bool Environment::operator!=(const Environment &other)
+bool Environment::operator!=(const Environment &other) const
 {
     return !(*this == other);
 }
 
-bool Environment::operator==(const Environment &other)
+bool Environment::operator==(const Environment &other) const
 {
     return m_values == other.m_values;
 }
diff --git a/src/plugins/projectexplorer/environment.h b/src/plugins/projectexplorer/environment.h
index 921b6795c6aeb53a6b3449aedb8a142e2e1f4236..1acec3291103df39b4adce6f681e12e61bc50745 100644
--- a/src/plugins/projectexplorer/environment.h
+++ b/src/plugins/projectexplorer/environment.h
@@ -94,8 +94,8 @@ public:
     static QStringList parseCombinedArgString(const QString &program);
     static QString joinArgumentList(const QStringList &arguments);
 
-    bool operator!=(const Environment &other);
-    bool operator==(const Environment &other);
+    bool operator!=(const Environment &other) const;
+    bool operator==(const Environment &other) const;
 private:
     QMap<QString, QString> m_values;
 };