diff --git a/Core/HLE/HLEHelperThread.cpp b/Core/HLE/HLEHelperThread.cpp
index 939a910c46..71b8bbc701 100644
--- a/Core/HLE/HLEHelperThread.cpp
+++ b/Core/HLE/HLEHelperThread.cpp
@@ -24,6 +24,7 @@
 #include "Core/HLE/KernelWaitHelpers.h"
 #include "Core/HLE/sceKernelThread.h"
 #include "Core/HLE/sceKernelMemory.h"
+#include "Core/MIPS/MIPS.h"
 #include "Core/MIPS/MIPSCodeUtils.h"
 
 HLEHelperThread::HLEHelperThread(const char *threadName, const u32 instructions[], u32 instrCount, u32 prio, int stacksize) {
@@ -36,6 +37,8 @@ HLEHelperThread::HLEHelperThread(const char *threadName, const u32 instructions[
 	// Just to simplify things, we add the return here.
 	Memory::WriteUnchecked_U32(MIPS_MAKE_JR_RA(), entry_ + instrBytes + 0);
 	Memory::WriteUnchecked_U32(MIPS_MAKE_NOP(), entry_ + instrBytes + 4);
+	// The memory may have held another helper's code, already compiled.
+	currentMIPS->InvalidateICacheRangeDeferred(entry_, totalBytes);
 
 	Create(threadName, prio, stacksize);
 }
@@ -46,6 +49,7 @@ HLEHelperThread::HLEHelperThread(const char *threadName, const char *module, con
 	_dbg_assert_(Memory::IsValid4AlignedAddress(entry_));  // after AllocEntry.
 	Memory::WriteUnchecked_U32(MIPS_MAKE_JR_RA(), entry_ + 0);
 	Memory::WriteUnchecked_U32(MIPS_MAKE_SYSCALL(module, func), entry_ + 4);
+	currentMIPS->InvalidateICacheRangeDeferred(entry_, bytes);
 
 	Create(threadName, prio, stacksize);
 }
diff --git a/Core/HLE/sceKernelModule.cpp b/Core/HLE/sceKernelModule.cpp
index 3b6883d972..403311b718 100644
--- a/Core/HLE/sceKernelModule.cpp
+++ b/Core/HLE/sceKernelModule.cpp
@@ -2808,6 +2808,8 @@ int __KernelStartModule(SceUID moduleId, u32 argsize, u32 argAddr, u32 returnVal
 				Memory::WriteUnchecked_U32(MIPS_MAKE_LW(MIPS_REG_RA, MIPS_REG_SP, 8), tramp + 0x24);
 				Memory::WriteUnchecked_U32(MIPS_MAKE_J(entryAddr), tramp + 0x28);
 				Memory::WriteUnchecked_U32(MIPS_MAKE_ADDIU(MIPS_REG_SP, MIPS_REG_SP, 16), tramp + 0x2C);
+				// Thread stacks get reused, so an older trampoline may already be compiled here.
+				currentMIPS->InvalidateICacheRangeDeferred(tramp, 0x30);
 				NotifyMemInfo(MemBlockFlags::WRITE, tramp, 0x30, "ModuleStartTrampoline");
 				startThread->context.pc = tramp;
 				startThread->nt.entrypoint = tramp;
diff --git a/Core/HLE/sceKernelThread.cpp b/Core/HLE/sceKernelThread.cpp
index 22d94cb22d..5bd4a67f7f 100644
--- a/Core/HLE/sceKernelThread.cpp
+++ b/Core/HLE/sceKernelThread.cpp
@@ -788,6 +788,8 @@ static void __KernelWriteFakeSysCall(u32 nid, u32 *ptr, u32 &pos) {
 	*ptr = pos;
 	pos += 8;
 	WriteHLESyscall("FakeSysCalls", nid, *ptr);
+	// The memory may have held code that's already compiled.
+	currentMIPS->InvalidateICacheRangeDeferred(*ptr, 8);
 }
 
 u32 HLEMipsCallReturnAddress() {
diff --git a/UI/ImDebugger/ImMemView.cpp b/UI/ImDebugger/ImMemView.cpp
index 85da5f27ab..d2c317ec9f 100644
--- a/UI/ImDebugger/ImMemView.cpp
+++ b/UI/ImDebugger/ImMemView.cpp
@@ -13,6 +13,7 @@
 #include "Common/File/FileUtil.h"
 #include "Core/Config.h"
 #include "Core/MemMap.h"
+#include "Core/MIPS/MIPS.h"
 #include "Core/Reporting.h"
 #include "Core/RetroAchievements.h"
 #include "Common/System/Display.h"
@@ -354,6 +355,7 @@ void ImMemView::EditMemory(int newNibble) {
 		out = (og & 0x0F) | (newNibble << 4);
 	}
 	Memory::WriteUnchecked_U8((u8)out, curAddress_);
+	currentMIPS->InvalidateICacheRangeDeferred(curAddress_ & ~3, 4);
 	ScrollCursor(1, GotoMode::RESET);
 }
 
@@ -365,8 +367,10 @@ void ImMemView::CopyToByteClipboard() {
 }
 
 void ImMemView::PasteFromByteClipboard() {
-	if (editableMemory_)
+	if (editableMemory_) {
 		Memory::MemcpyUnchecked(curAddress_, byteClipboard_.data(), (u32)byteClipboard_.size());
+		currentMIPS->InvalidateICacheRangeDeferred(curAddress_, (u32)byteClipboard_.size());
+	}
 }
 
 void ImMemView::toggleEditableMemory(bool toggle) {
@@ -388,6 +392,7 @@ void ImMemView::onChar(int c) {
 
 	if (asciiSelected_) {
 		Memory::WriteUnchecked_U8((u8)c, curAddress_);
+		currentMIPS->InvalidateICacheRangeDeferred(curAddress_ & ~3, 4);
 		ScrollCursor(1, GotoMode::RESET);
 	} else {
 		c = tolower(c);
@@ -403,6 +408,7 @@ void ImMemView::onChar(int c) {
 			oldValue &= ~(0xF << shiftAmount);
 			u8 newValue = oldValue | (inputValue << shiftAmount);
 			Memory::WriteUnchecked_U8(newValue, curAddress_);
+			currentMIPS->InvalidateICacheRangeDeferred(curAddress_ & ~3, 4);
 			ScrollCursor(1, GotoMode::RESET);
 		}
 	}
diff --git a/Windows/Debugger/CtrlMemView.cpp b/Windows/Debugger/CtrlMemView.cpp
index 4d0a7807ff..8ff58677d9 100644
--- a/Windows/Debugger/CtrlMemView.cpp
+++ b/Windows/Debugger/CtrlMemView.cpp
@@ -8,6 +8,7 @@
 #include "Core/Core.h"
 #include "Core/System.h"
 #include "Core/MemMap.h"
+#include "Core/MIPS/MIPS.h"
 #include "Core/Reporting.h"
 #include "Core/RetroAchievements.h"
 #include "Windows/W32Util/ContextMenu.h"
@@ -439,7 +440,10 @@ void CtrlMemView::onChar(WPARAM wParam, LPARAM lParam) {
 	// Route the actual memory write to the CPU thread instead of poking at it directly from this
 	// GUI thread - see Core_RunOnCPUThread() in Core.h. No need to force the core to pause first.
 	if (asciiSelected_) {
-		Core_RunOnCPUThread([&] { Memory::WriteUnchecked_U8((u8)wParam, curAddress_); });
+		Core_RunOnCPUThread([&] {
+			Memory::WriteUnchecked_U8((u8)wParam, curAddress_);
+			currentMIPS->InvalidateICacheRangeDeferred(curAddress_ & ~3, 4);
+		});
 		ScrollCursor(1, GotoMode::RESET);
 	} else {
 		wParam = tolower(wParam);
@@ -456,6 +460,7 @@ void CtrlMemView::onChar(WPARAM wParam, LPARAM lParam) {
 				oldValue &= ~(0xF << shiftAmount);
 				u8 newValue = oldValue | (inputValue << shiftAmount);
 				Memory::WriteUnchecked_U8(newValue, curAddress_);
+				currentMIPS->InvalidateICacheRangeDeferred(curAddress_ & ~3, 4);
 			});
 			ScrollCursor(1, GotoMode::RESET);
 		}