diff --git a/core/libs/prx/libc/src/GuestHeap.cpp b/core/libs/prx/libc/src/GuestHeap.cpp
index ae9d1674c..89efffce7 100644
--- a/core/libs/prx/libc/src/GuestHeap.cpp
+++ b/core/libs/prx/libc/src/GuestHeap.cpp
@@ -24,7 +24,8 @@ namespace {
 
 // Each block is preceded by a header holding the raw block address and its size in bytes.
 constexpr std::size_t HeaderBytes = 2 * sizeof(void*);
-constexpr std::size_t MinimumAlignment = 16;
+constexpr std::size_t RawAlignment = 16;
+constexpr std::size_t MinimumAlignment = 32;
 constexpr std::size_t PageBytes = 0x4000;
 constexpr std::size_t SpanBytes = 1u << 20;
 constexpr std::size_t MaximumSmallBytes = 64u * 1024u;
@@ -200,7 +201,7 @@ void rawFree(void* raw, std::size_t blockBytes) {
 void* allocate(GuestAllocations::Mutation& mutation, std::size_t alignment, std::size_t bytes) {
     if (alignment == 0 || (alignment & (alignment - 1)) != 0) throw std::invalid_argument("invalid guest heap alignment");
     alignment = std::max(alignment, MinimumAlignment);
-    const std::size_t padding = alignment > MinimumAlignment ? alignment : 0;
+    const std::size_t padding = alignment > RawAlignment ? alignment : 0;
     if (bytes > std::numeric_limits<std::size_t>::max() - HeaderBytes - padding) throw std::length_error("guest heap allocation overflow");
     std::size_t blockBytes = 0;
     void* raw = rawAllocate(bytes + HeaderBytes + padding, blockBytes);
diff --git a/core/libs/tests/GuestMemory.cpp b/core/libs/tests/GuestMemory.cpp
index 892cefb40..d3b10f393 100644
--- a/core/libs/tests/GuestMemory.cpp
+++ b/core/libs/tests/GuestMemory.cpp
@@ -664,6 +664,24 @@ static void CheckSharedDirectMemoryLifecycle() {
     Require(sceKernelReleaseDirectMemory(phys, page * 3) == 0);
 }
 
+static void CheckHeapAlignment() {
+    std::vector<std::pair<unsigned char*, std::size_t>> blocks;
+    for (std::size_t bytes = 1; bytes <= 600; ++bytes) blocks.emplace_back(static_cast<unsigned char*>(GuestHeap::GuestHeapAllocate_nid_postfix(bytes)), bytes);
+    for (const std::size_t bytes : {std::size_t{4000}, std::size_t{70000}, std::size_t{0x30000}}) blocks.emplace_back(static_cast<unsigned char*>(GuestHeap::GuestHeapAllocate_nid_postfix(bytes)), bytes);
+    auto* grown = static_cast<unsigned char*>(GuestHeap::GuestHeapReallocate_nid_postfix(GuestHeap::GuestHeapAllocate_nid_postfix(8), 333));
+    blocks.emplace_back(grown, 333);
+    for (std::size_t index = 0; index < blocks.size(); ++index) {
+        const auto [pointer, bytes] = blocks[index];
+        Require((reinterpret_cast<std::uintptr_t>(pointer) & 31u) == 0);
+        std::memset(pointer, static_cast<int>(index & 0xffu), bytes);
+    }
+    for (std::size_t index = 0; index < blocks.size(); ++index) {
+        const auto [pointer, bytes] = blocks[index];
+        for (std::size_t at = 0; at < bytes; ++at) Require(pointer[at] == static_cast<unsigned char>(index & 0xffu));
+        GuestHeap::GuestHeapFree_nid_postfix(pointer);
+    }
+}
+
 static void CheckHeapAfterMappingReuse() {
     constexpr std::size_t bytes = 0x30000;
     auto* pointer = static_cast<unsigned char*>(GuestHeap::GuestHeapAllocate_nid_postfix(bytes));
@@ -1080,6 +1098,7 @@ int main() {
     CheckSharedDirectMemoryLifecycle();
     CheckGetDirectMemoryType();
     CheckMtypeprotect();
+    CheckHeapAlignment();
     CheckHeapAfterMappingReuse();
 #ifdef _WIN32
     CheckNoOverwriteRejectsHostOccupiedMapping();