diff --git a/cmake/compiler_utils.cmake b/cmake/compiler_utils.cmake
index 4fca09284..59080fd99 100644
--- a/cmake/compiler_utils.cmake
+++ b/cmake/compiler_utils.cmake
@@ -9,6 +9,10 @@ endfunction()
 function(compiler_get_warnings_setup VARNAME)
     if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
         set(WARNINGS_SETUP "-Wall -Wextra -pedantic -Wconversion -Wno-long-long")
+        # gcc 7.5 reports Wsign-conversion even on static_cast, reportedly fixed in gcc 9.3
+        if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "9.3.0")
+            set(WARNINGS_SETUP "${WARNINGS_SETUP} -Wsign-conversion")
+        endif ()
     elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
         set(WARNINGS_SETUP_LIST "-Weverything"
                 "-Wno-system-headers"
diff --git a/compiler/extensions/cpp/runtime/src/zserio/BitStreamReader.cpp b/compiler/extensions/cpp/runtime/src/zserio/BitStreamReader.cpp
index 77b17cd74..00578c095 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/BitStreamReader.cpp
+++ b/compiler/extensions/cpp/runtime/src/zserio/BitStreamReader.cpp
@@ -435,7 +435,7 @@ int64_t BitStreamReader::readSignedBits64(uint8_t numBits)
             numBits < 64 && (static_cast<uint64_t>(value) >= (UINT64_C(1) << (numBits - 1)));
     if (needsSignExtension)
     {
-        value -= UINT64_C(1) << numBits;
+        value = static_cast<int64_t>(static_cast<uint64_t>(value) - (UINT64_C(1) << numBits));
     }
 
     return value;
diff --git a/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.cpp b/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.cpp
index e9f5be797..3d26c65e0 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.cpp
+++ b/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.cpp
@@ -656,7 +656,7 @@ inline void BitStreamWriter::writeVarNum(
         }
 
         const size_t shiftBits = (numVarBytes - (i + 1)) * 7 + ((hasMaxByteRange && hasNextByte) ? 1 : 0);
-        const uint8_t add = static_cast<uint8_t>((value >> shiftBits) & bitMasks[numBits - 1]);
+        const uint8_t add = static_cast<uint8_t>((value >> shiftBits) & bitMasks[numBits - 1U]);
         byte = static_cast<uint8_t>(byte | add);
         writeUnsignedBits(byte, 8);
     }
diff --git a/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.h b/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.h
index 7261528fe..d263ba4c0 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.h
+++ b/compiler/extensions/cpp/runtime/src/zserio/BitStreamWriter.h
@@ -264,7 +264,7 @@ class BitStreamWriter
 
         if (numRestBits > 0)
         {
-            writeUnsignedBits(*itEnd >> (8U - numRestBits), numRestBits);
+            writeUnsignedBits(static_cast<uint32_t>(*itEnd) >> (8U - numRestBits), numRestBits);
         }
     }
 
diff --git a/compiler/extensions/cpp/runtime/src/zserio/DeltaContext.h b/compiler/extensions/cpp/runtime/src/zserio/DeltaContext.h
index bf587daf6..b2f25b0a4 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/DeltaContext.h
+++ b/compiler/extensions/cpp/runtime/src/zserio/DeltaContext.h
@@ -139,7 +139,7 @@ class DeltaContext
         }
         else
         {
-            return m_maxBitNumber + (m_maxBitNumber > 0 ? 1 : 0);
+            return static_cast<size_t>(m_maxBitNumber) + (m_maxBitNumber > 0 ? 1 : 0);
         }
     }
 
@@ -273,8 +273,8 @@ class DeltaContext
     {
         if (isFlagSet(IS_PACKED_FLAG))
         {
-            const size_t deltaBitSize = m_maxBitNumber + (m_maxBitNumber > 0 ? 1 : 0);
-            const size_t packedBitSizeWithDescriptor = 1 + MAX_BIT_NUMBER_BITS + // descriptor
+            const size_t deltaBitSize = static_cast<size_t>(m_maxBitNumber) + (m_maxBitNumber > 0 ? 1 : 0);
+            const size_t packedBitSizeWithDescriptor = 1U + MAX_BIT_NUMBER_BITS + // descriptor
                     m_firstElementBitSize + (m_numElements - 1) * deltaBitSize;
             const size_t unpackedBitSizeWithDescriptor = 1 + m_unpackedBitSize;
             if (packedBitSizeWithDescriptor >= unpackedBitSizeWithDescriptor)
diff --git a/compiler/extensions/cpp/runtime/src/zserio/FloatUtil.cpp b/compiler/extensions/cpp/runtime/src/zserio/FloatUtil.cpp
index 480fc519d..b7b7d92e2 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/FloatUtil.cpp
+++ b/compiler/extensions/cpp/runtime/src/zserio/FloatUtil.cpp
@@ -65,7 +65,7 @@ float convertUInt16ToFloat(uint16_t float16Value)
     else
     {
         // normal number
-        exponent32 = exponent16 - FLOAT16_EXPONENT_BIAS + FLOAT32_EXPONENT_BIAS;
+        exponent32 = static_cast<uint32_t>(exponent16) - FLOAT16_EXPONENT_BIAS + FLOAT32_EXPONENT_BIAS;
     }
 
     // compose single precision float (float32)
diff --git a/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h b/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h
index 62a8aec88..eb5e5e279 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h
+++ b/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h
@@ -1440,7 +1440,7 @@ const IBasicTypeInfo<ALLOC>& FixedSizeBuiltinTypeInfo<ALLOC>::getFixedSignedBitF
                     {"int:63"_sv, SchemaType::FIXED_SIGNED_BITFIELD, CppType::INT64, 63},
                     {"int:64"_sv, SchemaType::FIXED_SIGNED_BITFIELD, CppType::INT64, 64}}};
 
-    return bitFieldTypeInfoArray[bitSize - 1];
+    return bitFieldTypeInfoArray[bitSize - 1U];
 }
 
 template <typename ALLOC>
@@ -1518,7 +1518,7 @@ const IBasicTypeInfo<ALLOC>& FixedSizeBuiltinTypeInfo<ALLOC>::getFixedUnsignedBi
                     {"bit:63"_sv, SchemaType::FIXED_UNSIGNED_BITFIELD, CppType::UINT64, 63},
                     {"bit:64"_sv, SchemaType::FIXED_UNSIGNED_BITFIELD, CppType::UINT64, 64}}};
 
-    return bitFieldTypeInfoArray[bitSize - 1];
+    return bitFieldTypeInfoArray[static_cast<size_t>(bitSize - 1)];
 }
 
 template <typename ALLOC>
diff --git a/compiler/extensions/cpp/runtime/test/zserio/BitStreamReaderTest.cpp b/compiler/extensions/cpp/runtime/test/zserio/BitStreamReaderTest.cpp
index 6adab2bc1..5a937ae9f 100644
--- a/compiler/extensions/cpp/runtime/test/zserio/BitStreamReaderTest.cpp
+++ b/compiler/extensions/cpp/runtime/test/zserio/BitStreamReaderTest.cpp
@@ -85,7 +85,7 @@ TEST_F(BitStreamReaderTest, readUnalignedData)
 
     for (uint8_t offset = 0; offset <= 64; ++offset)
     {
-        BitBuffer buffer(8 + offset);
+        BitBuffer buffer(8U + offset);
 
         // write test value at offset to data buffer
         buffer.getData()[offset / 8U] = static_cast<uint8_t>(
diff --git a/compiler/extensions/cpp/runtime/test/zserio/BitStreamWriterTest.cpp b/compiler/extensions/cpp/runtime/test/zserio/BitStreamWriterTest.cpp
index 47b498f1b..6a22d42a8 100644
--- a/compiler/extensions/cpp/runtime/test/zserio/BitStreamWriterTest.cpp
+++ b/compiler/extensions/cpp/runtime/test/zserio/BitStreamWriterTest.cpp
@@ -119,7 +119,7 @@ TEST_F(BitStreamWriterTest, writeUnalignedData)
 
     for (uint8_t offset = 0; offset <= 64; ++offset)
     {
-        BitBuffer bitBuffer(8 + offset);
+        BitBuffer bitBuffer(8U + offset);
         // fill the buffer with 1s to check proper masking
         std::memset(bitBuffer.getBuffer(), 0xFF, bitBuffer.getByteSize());
 
diff --git a/test/arguments/set_cpp_allocator/cpp/ComplexAllocationTest.cpp b/test/arguments/set_cpp_allocator/cpp/ComplexAllocationTest.cpp
index 2f86fa30d..b162b584a 100644
--- a/test/arguments/set_cpp_allocator/cpp/ComplexAllocationTest.cpp
+++ b/test/arguments/set_cpp_allocator/cpp/ComplexAllocationTest.cpp
@@ -129,15 +129,18 @@ class ComplexAllocationTest : public ::testing::Test
 
         // externalField
         writer.writeVarSize(EXTERNAL_FIELD_VAR_SIZE);
-        writer.writeBits(EXTERNAL_FIELD_DATA >> (8U - (EXTERNAL_FIELD_VAR_SIZE % 8U)), EXTERNAL_FIELD_VAR_SIZE);
+        writer.writeBits(static_cast<uint32_t>(EXTERNAL_FIELD_DATA) >> (8U - (EXTERNAL_FIELD_VAR_SIZE % 8U)),
+                EXTERNAL_FIELD_VAR_SIZE);
 
         // externalArray
         writer.writeVarSize(EXTERNAL_ARRAY_SIZE);
         writer.writeVarSize(EXTERNAL_ARRAY_ELEMENT0_VAR_SIZE);
-        writer.writeBits(EXTERNAL_ARRAY_ELEMENT0_DATA >> (8U - (EXTERNAL_ARRAY_ELEMENT0_VAR_SIZE % 8U)),
+        writer.writeBits(static_cast<uint32_t>(EXTERNAL_ARRAY_ELEMENT0_DATA) >>
+                        (8U - (EXTERNAL_ARRAY_ELEMENT0_VAR_SIZE % 8U)),
                 EXTERNAL_ARRAY_ELEMENT0_VAR_SIZE);
         writer.writeVarSize(EXTERNAL_ARRAY_ELEMENT1_VAR_SIZE);
-        writer.writeBits(EXTERNAL_ARRAY_ELEMENT1_DATA >> (8U - (EXTERNAL_ARRAY_ELEMENT1_VAR_SIZE % 8U)),
+        writer.writeBits(static_cast<uint32_t>(EXTERNAL_ARRAY_ELEMENT1_DATA) >>
+                        (8U - (EXTERNAL_ARRAY_ELEMENT1_VAR_SIZE % 8U)),
                 EXTERNAL_ARRAY_ELEMENT1_VAR_SIZE);
 
         // bytesField
diff --git a/test/language/array_types/cpp/PackedAutoArrayUInt8Test.cpp b/test/language/array_types/cpp/PackedAutoArrayUInt8Test.cpp
index fa6aad4ef..852e9a32a 100644
--- a/test/language/array_types/cpp/PackedAutoArrayUInt8Test.cpp
+++ b/test/language/array_types/cpp/PackedAutoArrayUInt8Test.cpp
@@ -38,7 +38,7 @@ class PackedAutoArrayUInt8Test : public ::testing::Test
             bitSize += 6; // packing descriptor: maxBitNumber
         }
         bitSize += 8; // first element
-        bitSize += (numElements - 1) * (PACKED_ARRAY_MAX_BIT_NUMBER + 1); // all deltas
+        bitSize += (numElements - 1) * (PACKED_ARRAY_MAX_BIT_NUMBER + 1U); // all deltas
 
         return bitSize;
     }
diff --git a/test/language/array_types/cpp/PackedVariableArrayStructRecursionTest.cpp b/test/language/array_types/cpp/PackedVariableArrayStructRecursionTest.cpp
index 7782f46dd..c83d63784 100644
--- a/test/language/array_types/cpp/PackedVariableArrayStructRecursionTest.cpp
+++ b/test/language/array_types/cpp/PackedVariableArrayStructRecursionTest.cpp
@@ -64,7 +64,7 @@ class PackedVariableArrayStructRecursionTest : public ::testing::Test
 
     size_t getUnpackedBlockBitSize(uint8_t byteCount, bool isLast)
     {
-        size_t bitSize = 8 * byteCount; // dataBytes[byteCount]
+        size_t bitSize = 8U * byteCount; // dataBytes[byteCount]
         bitSize += 8; // blockTerminator
         if (!isLast)
         {
diff --git a/test/language/array_types/cpp/PackedVariableArrayUInt8Test.cpp b/test/language/array_types/cpp/PackedVariableArrayUInt8Test.cpp
index 20b31524a..abc07961d 100644
--- a/test/language/array_types/cpp/PackedVariableArrayUInt8Test.cpp
+++ b/test/language/array_types/cpp/PackedVariableArrayUInt8Test.cpp
@@ -40,7 +40,7 @@ class PackedVariableArrayUInt8Test : public ::testing::Test
             bitSize += 6; // packing descriptor: maxBitNumber
         }
         bitSize += 8; // first element
-        bitSize += (numElements - 1) * (PACKED_ARRAY_MAX_BIT_NUMBER + 1); // all deltas
+        bitSize += (numElements - 1) * (PACKED_ARRAY_MAX_BIT_NUMBER + 1U); // all deltas
 
         return bitSize;
     }
diff --git a/test/language/offsets/cpp/PackedAutoArrayOffsetTest.cpp b/test/language/offsets/cpp/PackedAutoArrayOffsetTest.cpp
index c008a89a5..c09ab3837 100644
--- a/test/language/offsets/cpp/PackedAutoArrayOffsetTest.cpp
+++ b/test/language/offsets/cpp/PackedAutoArrayOffsetTest.cpp
@@ -59,7 +59,7 @@ class PackedAutoArrayOffsetTest : public ::testing::Test
         bitSize += 1; // packing descriptor: isPacked
         bitSize += 6; // packing descriptor: maxBitNumber
         bitSize += 7; // first element
-        bitSize += (AUTO_ARRAY_LENGTH - 1) * (PACKED_ARRAY_MAX_BIT_NUMBER + 1); // all deltas
+        bitSize += (AUTO_ARRAY_LENGTH - 1) * (PACKED_ARRAY_MAX_BIT_NUMBER + 1U); // all deltas
 
         return bitSize;
     }
diff --git a/test/language/parameterized_types/cpp/ArrayElementParamTest.cpp b/test/language/parameterized_types/cpp/ArrayElementParamTest.cpp
index bdaa4591f..adc74ae70 100644
--- a/test/language/parameterized_types/cpp/ArrayElementParamTest.cpp
+++ b/test/language/parameterized_types/cpp/ArrayElementParamTest.cpp
@@ -53,7 +53,7 @@ class ArrayElementParamTest : public ::testing::Test
             const uint16_t numItems = static_cast<uint16_t>(reader.readBits(16));
             ASSERT_EQ(headers.at(i).getNumItems(), numItems);
             ASSERT_EQ(expectedOffset, reader.readBits(32));
-            expectedOffset += 8 * numItems;
+            expectedOffset += 8U * numItems;
         }
 
         const auto& blocks = database.getBlocks();
diff --git a/test/language/parameterized_types/cpp/PackedArrayElementParamTest.cpp b/test/language/parameterized_types/cpp/PackedArrayElementParamTest.cpp
index 9fae3dd20..9249470cd 100644
--- a/test/language/parameterized_types/cpp/PackedArrayElementParamTest.cpp
+++ b/test/language/parameterized_types/cpp/PackedArrayElementParamTest.cpp
@@ -43,7 +43,7 @@ class PackedArrayElementParamTest : public ::testing::Test
     size_t getUnpackedDatabaseBitSize(uint16_t numBlocks)
     {
         size_t bitSize = 16; // numBlocks
-        bitSize += numBlocks * (16 + 32); // headers
+        bitSize += static_cast<size_t>(numBlocks) * (16 + 32); // headers
         for (size_t i = 0; i < numBlocks; ++i)
         {
             bitSize += 64 + (i + 1) * 64; // blocks[i]