diff --git a/src/Magnum/ShaderTools/AbstractConverter.cpp b/src/Magnum/ShaderTools/AbstractConverter.cpp
index 820f1e9ae..8e70275d0 100644
--- a/src/Magnum/ShaderTools/AbstractConverter.cpp
+++ b/src/Magnum/ShaderTools/AbstractConverter.cpp
@@ -84,6 +84,8 @@ ConverterFeatures AbstractConverter::features() const {
 }
 
 void AbstractConverter::setFlags(const ConverterFlags flags) {
+    CORRADE_ASSERT(!(flags & ConverterFlag::Quiet) != !(flags & ConverterFlag::Verbose),
+        "ShaderTools::AbstractConverter::setFeatures(): can't have both Quiet and Verbose set", );
     _flags = flags;
     doSetFlags(flags);
 }
@@ -642,7 +644,9 @@ Debug& operator<<(Debug& debug, const ConverterFlag value) {
     switch(value) {
         /* LCOV_EXCL_START */
         #define _c(v) case ConverterFlag::v: return debug << "::" #v;
+        _c(Quiet)
         _c(Verbose)
+        _c(WarningAsError)
         #undef _c
         /* LCOV_EXCL_STOP */
     }
@@ -652,7 +656,10 @@ Debug& operator<<(Debug& debug, const ConverterFlag value) {
 
 Debug& operator<<(Debug& debug, const ConverterFlags value) {
     return Containers::enumSetDebugOutput(debug, value, "ShaderTools::ConverterFlags{}", {
-        ConverterFlag::Verbose});
+        ConverterFlag::Quiet,
+        ConverterFlag::Verbose,
+        ConverterFlag::WarningAsError
+    });
 }
 
 Debug& operator<<(Debug& debug, const Format value) {
diff --git a/src/Magnum/ShaderTools/AbstractConverter.h b/src/Magnum/ShaderTools/AbstractConverter.h
index 5d77c569f..85abd2109 100644
--- a/src/Magnum/ShaderTools/AbstractConverter.h
+++ b/src/Magnum/ShaderTools/AbstractConverter.h
@@ -126,11 +126,25 @@ MAGNUM_SHADERTOOLS_EXPORT Debug& operator<<(Debug& debug, ConverterFeatures valu
 @see @ref ConverterFlags, @ref AbstractConverter::setFlags()
 */
 enum class ConverterFlag: UnsignedInt {
+    /**
+     * Suppress warnings, print just errors. By default the converter prints
+     * both warnings and errors.
+     * @see @ref ConverterFlag::WarningAsError
+     */
+    Quiet = 1 << 0,
+
     /**
      * Print verbose diagnostic. By default the converter only prints warnings
      * and errors.
      */
-    Verbose = 1 << 0
+    Verbose = 1 << 1,
+
+    /**
+     * Treat warnings as error. By default, if a warning occurs,
+     * validation or conversion succeeds. With this flag set, it fails.
+     * @see @ref ConverterFlag::Quiet
+     */
+    WarningAsError = 1 << 2
 };
 
 /**
diff --git a/src/Magnum/ShaderTools/Test/AbstractConverterTest.cpp b/src/Magnum/ShaderTools/Test/AbstractConverterTest.cpp
index ee732b525..fad87e037 100644
--- a/src/Magnum/ShaderTools/Test/AbstractConverterTest.cpp
+++ b/src/Magnum/ShaderTools/Test/AbstractConverterTest.cpp
@@ -47,6 +47,7 @@ struct AbstractConverterTest: TestSuite::Tester {
     void featuresNone();
 
     void setFlags();
+    void setFlagsBothQuietAndVerbose();
     void setFlagsNotImplemented();
 
     void setInputOutputFormat();
@@ -166,6 +167,7 @@ AbstractConverterTest::AbstractConverterTest() {
     addTests({&AbstractConverterTest::featuresNone,
 
               &AbstractConverterTest::setFlags,
+              &AbstractConverterTest::setFlagsBothQuietAndVerbose,
               &AbstractConverterTest::setFlagsNotImplemented,
 
               &AbstractConverterTest::setInputOutputFormat,
@@ -326,6 +328,25 @@ void AbstractConverterTest::setFlags() {
     CORRADE_COMPARE(converter._flags, ConverterFlag::Verbose);
 }
 
+void AbstractConverterTest::setFlagsBothQuietAndVerbose() {
+    #ifdef CORRADE_NO_ASSERT
+    CORRADE_SKIP("CORRADE_NO_ASSERT defined, can't test assertions");
+    #endif
+
+    struct: AbstractConverter {
+        ConverterFeatures doFeatures() const override {
+            return ConverterFeature::ValidateData;
+        }
+        void doSetInputFormat(Format, Containers::StringView) override {}
+        void doSetOutputFormat(Format, Containers::StringView) override {}
+    } converter;
+
+    std::ostringstream out;
+    Error redirectError{&out};
+    converter.setFlags(ConverterFlag::Quiet|ConverterFlag::Verbose);
+    CORRADE_COMPARE(out.str(), "ShaderTools::AbstractConverter::setFlags(): can't have both Quiet and Verbose set\n");
+}
+
 void AbstractConverterTest::setFlagsNotImplemented() {
     struct: AbstractConverter {
         ConverterFeatures doFeatures() const override {