diff --git a/Core/BizhawkMovie.cpp b/Core/BizhawkMovie.cpp
index 4492cec3..beb505bf 100644
--- a/Core/BizhawkMovie.cpp
+++ b/Core/BizhawkMovie.cpp
@@ -20,7 +20,7 @@ void BizhawkMovie::ProcessNotification(ConsoleNotificationType type, void* param
 {
 	if(type == ConsoleNotificationType::PpuFrameDone) {
 		int32_t frameNumber = PPU::GetFrameCount() - 1;
-		if(frameNumber < _systemActionByFrame.size()) {
+		if(frameNumber < (int32_t)_systemActionByFrame.size()) {
 			uint32_t systemAction = _systemActionByFrame[frameNumber];
 			if(systemAction & 0x01) {
 				//Power, not implemented yet
@@ -61,7 +61,7 @@ void BizhawkMovie::ProcessNotification(ConsoleNotificationType type, void* param
 uint8_t BizhawkMovie::GetState(uint8_t port)
 {
 	int32_t frameNumber = PPU::GetFrameCount() - 1;
-	if(frameNumber < _dataByFrame[0].size()) {
+	if(frameNumber < (int32_t)_dataByFrame[0].size()) {
 		return _dataByFrame[port][frameNumber];
 	} else {
 		EndMovie();
@@ -137,7 +137,7 @@ bool BizhawkMovie::InitializeInputData(ZipReader & reader)
 
 				if(port <= 3) {
 					uint8_t portValue = 0;
-					for(int j = 0; j < 8 && i + j + systemActionCount < line.size(); j++) {
+					for(int j = 0; j < 8 && i + j + systemActionCount < (int)line.size(); j++) {
 						if(line[i+j+systemActionCount] != '.') {
 							portValue |= orValues[j];
 						}
diff --git a/Core/Debugger.cpp b/Core/Debugger.cpp
index 13dd7402..4a3f9a3d 100644
--- a/Core/Debugger.cpp
+++ b/Core/Debugger.cpp
@@ -682,7 +682,7 @@ void Debugger::ProcessVramOperation(MemoryOperationType type, uint16_t addr, uin
 void Debugger::GetCallstack(int32_t* callstackAbsolute, int32_t* callstackRelative)
 {
 	int callstackSize = (int)_callstackRelative.size() - (_hideTopOfCallstack ? 2 : 0);
-	for(size_t i = 0; i < callstackSize; i++) {
+	for(int i = 0; i < callstackSize; i++) {
 		callstackAbsolute[i] = _callstackAbsolute[i];
 		
 		int32_t relativeAddr = _callstackRelative[i];
diff --git a/Core/FDS.cpp b/Core/FDS.cpp
index 8ec5e839..648fdf85 100644
--- a/Core/FDS.cpp
+++ b/Core/FDS.cpp
@@ -93,7 +93,7 @@ uint8_t FDS::ReadRAM(uint16_t addr)
 			buffer[i] = CPU::DebugReadByte(bufferAddr + i);
 		}
 
-		for(int j = 0; j < _fdsDiskHeaders.size(); j++) {
+		for(int j = 0; j < (int)_fdsDiskHeaders.size(); j++) {
 			bool match = true;
 			for(int i = 0; i < 10; i++) {
 				if(buffer[i] != 0xFF && buffer[i] != _fdsDiskHeaders[j][i + 14]) {
diff --git a/Utilities/sha1.cpp b/Utilities/sha1.cpp
index 1cb68af6..dbae07bc 100644
--- a/Utilities/sha1.cpp
+++ b/Utilities/sha1.cpp
@@ -237,7 +237,7 @@ void SHA1::update(std::istream &is)
 
 	while(true) {
 		is.read(sbuf, BLOCK_BYTES - buffer.size());
-		buffer.append(sbuf, is.gcount());
+		buffer.append(sbuf, (size_t)is.gcount());
 		if(buffer.size() != BLOCK_BYTES) {
 			return;
 		}