diff --git a/src/coreclr/pal/src/exception/signal.cpp b/src/coreclr/pal/src/exception/signal.cpp
index 4a5cfac1d41ea5..3d7edb2cf8147d 100644
--- a/src/coreclr/pal/src/exception/signal.cpp
+++ b/src/coreclr/pal/src/exception/signal.cpp
@@ -190,13 +190,20 @@ BOOL SEHInitializeSignals(CorUnix::CPalThread *pthrCurrent, DWORD flags)
         handle_signal(SIGSEGV, sigsegv_handler, &g_previous_sigsegv);
 #else
         handle_signal(SIGTRAP, sigtrap_handler, &g_previous_sigtrap);
+        int additionalFlagsForSigSegv = 0;
+#ifndef TARGET_SUNOS
+        // On platforms that support it,
         // SIGSEGV handler runs on a separate stack so that we can handle stack overflow
-        handle_signal(SIGSEGV, sigsegv_handler, &g_previous_sigsegv, SA_ONSTACK);
+        additionalFlagsForSigSegv |= SA_ONSTACK;
+#endif
+        handle_signal(SIGSEGV, sigsegv_handler, &g_previous_sigsegv, additionalFlagsForSigSegv);
 
+#ifndef TARGET_SUNOS
         if (!pthrCurrent->EnsureSignalAlternateStack())
         {
             return FALSE;
         }
+#endif
 
         // Allocate the minimal stack necessary for handling stack overflow
         int stackOverflowStackSize = ALIGN_UP(sizeof(SignalHandlerWorkerReturnPoint), 16) + 7 * 4096;
@@ -344,7 +351,7 @@ Return :
 --*/
 bool IsRunningOnAlternateStack(void *context)
 {
-#if HAVE_MACH_EXCEPTIONS
+#if HAVE_MACH_EXCEPTIONS || defined(TARGET_SUNOS)
     return false;
 #else
     bool isRunningOnAlternateStack;
@@ -656,6 +663,7 @@ static void sigsegv_handler(int code, siginfo_t *siginfo, void *context)
             // Now that we know the SIGSEGV didn't happen due to a stack overflow, execute the common
             // hardware signal handler on the original stack.
 
+#ifndef TARGET_SUNOS
             if (GetCurrentPalThread() && IsRunningOnAlternateStack(context))
             {
                 if (SwitchStackAndExecuteHandler(code, siginfo, context, 0 /* sp */)) // sp == 0 indicates execution on the original stack
@@ -664,6 +672,7 @@ static void sigsegv_handler(int code, siginfo_t *siginfo, void *context)
                 }
             }
             else
+#endif
             {
                 // The code flow gets here when the signal handler is not running on an alternate stack or when it wasn't created
                 // by coreclr. In both cases, we execute the common_signal_handler directly.
diff --git a/src/coreclr/pal/src/include/pal/thread.hpp b/src/coreclr/pal/src/include/pal/thread.hpp
index 411040f39b21a5..e45d7d8faa0b79 100644
--- a/src/coreclr/pal/src/include/pal/thread.hpp
+++ b/src/coreclr/pal/src/include/pal/thread.hpp
@@ -288,8 +288,11 @@ namespace CorUnix
         void* m_stackBase;
         // Limit address of the stack of this thread
         void* m_stackLimit;
+
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
         // Signal handler's alternate stack to help with stack overflow
         void* m_alternateStack;
+#endif
 
         //
         // The thread entry routine (called from InternalCreateThread)
@@ -343,8 +346,10 @@ namespace CorUnix
             m_fStartStatus(FALSE),
             m_fStartStatusSet(FALSE),
             m_stackBase(NULL),
-            m_stackLimit(NULL),
-            m_alternateStack(NULL)
+            m_stackLimit(NULL)
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
+            ,m_alternateStack(NULL)
+#endif
         {
         };
 
@@ -588,7 +593,7 @@ namespace CorUnix
             m_pNext = pNext;
         };
 
-#if !HAVE_MACH_EXCEPTIONS
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
         BOOL
         EnsureSignalAlternateStack(
             void
diff --git a/src/coreclr/pal/src/init/sxs.cpp b/src/coreclr/pal/src/init/sxs.cpp
index 4c1772896a99ca..b7e17c106c4a6d 100644
--- a/src/coreclr/pal/src/init/sxs.cpp
+++ b/src/coreclr/pal/src/init/sxs.cpp
@@ -64,7 +64,7 @@ AllocatePalThread(CPalThread **ppThread)
         goto exit;
     }
 
-#if !HAVE_MACH_EXCEPTIONS
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
     // Ensure alternate stack for SIGSEGV handling. Our SIGSEGV handler is set to
     // run on an alternate stack and the stack needs to be allocated per thread.
     if (!pThread->EnsureSignalAlternateStack())
diff --git a/src/coreclr/pal/src/thread/thread.cpp b/src/coreclr/pal/src/thread/thread.cpp
index abfde0de726f32..97b7c180d7af2a 100644
--- a/src/coreclr/pal/src/thread/thread.cpp
+++ b/src/coreclr/pal/src/thread/thread.cpp
@@ -157,7 +157,7 @@ static void InternalEndCurrentThreadWrapper(void *arg)
        will lock its own critical section */
     LOADCallDllMain(DLL_THREAD_DETACH, NULL);
 
-#if !HAVE_MACH_EXCEPTIONS
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
     pThread->FreeSignalAlternateStack();
 #endif // !HAVE_MACH_EXCEPTIONS
 
@@ -1667,7 +1667,7 @@ CPalThread::ThreadEntry(
     }
 #endif // HAVE_SCHED_GETAFFINITY && HAVE_SCHED_SETAFFINITY
 
-#if !HAVE_MACH_EXCEPTIONS
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
     if (!pThread->EnsureSignalAlternateStack())
     {
         ASSERT("Cannot allocate alternate stack for SIGSEGV!\n");
@@ -2390,7 +2390,7 @@ CPalThread::WaitForStartStatus(
     return m_fStartStatus;
 }
 
-#if !HAVE_MACH_EXCEPTIONS
+#if !HAVE_MACH_EXCEPTIONS && !defined(TARGET_SUNOS)
 /*++
 Function :
     EnsureSignalAlternateStack