diff --git a/src/util/CMakeLists.txt b/src/util/CMakeLists.txt
index 7a7437843..6aa4f0e40 100644
--- a/src/util/CMakeLists.txt
+++ b/src/util/CMakeLists.txt
@@ -77,7 +77,7 @@ target_precompile_headers(util PRIVATE "pch.h")
 target_include_directories(util PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/..")
 target_include_directories(util PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/..")
 target_link_libraries(util PUBLIC common simpleini imgui)
-target_link_libraries(util PRIVATE libchdr JPEG::JPEG PNG::PNG WebP::libwebp lunasvg::lunasvg ZLIB::ZLIB SoundTouch::SoundTouchDLL xxhash Zstd::Zstd reshadefx)
+target_link_libraries(util PRIVATE libchdr lzma JPEG::JPEG PNG::PNG WebP::libwebp lunasvg::lunasvg ZLIB::ZLIB SoundTouch::SoundTouchDLL xxhash Zstd::Zstd reshadefx)
 
 if(ENABLE_X11)
   target_compile_definitions(util PRIVATE "-DENABLE_X11=1")
diff --git a/src/util/compress_helpers.cpp b/src/util/compress_helpers.cpp
index 44db92712..e20efc2fe 100644
--- a/src/util/compress_helpers.cpp
+++ b/src/util/compress_helpers.cpp
@@ -3,15 +3,26 @@
 
 #include "compress_helpers.h"
 
+#include "common/align.h"
 #include "common/assert.h"
 #include "common/error.h"
 #include "common/file_system.h"
+#include "common/log.h"
 #include "common/path.h"
+#include "common/scoped_guard.h"
 #include "common/string_util.h"
 
+#include "7zCrc.h"
+#include "Alloc.h"
+#include "Xz.h"
+#include "XzCrc64.h"
+#include "XzEnc.h"
+
 #include <zstd.h>
 #include <zstd_errors.h>
 
+LOG_CHANNEL(CompressHelpers);
+
 // TODO: Use streaming API to avoid mallocing the whole input buffer. But one read() call is probably still faster..
 
 namespace CompressHelpers {
@@ -23,13 +34,284 @@ static bool DecompressHelper(OptionalByteBuffer& ret, CompressType type, T data,
 
 template<typename T>
 static bool CompressHelper(OptionalByteBuffer& ret, CompressType type, T data, int clevel, Error* error);
+
+static void Init7ZCRCTables();
+static bool XzCompress(OptionalByteBuffer& ret, const u8* data, size_t data_size, int clevel, Error* error);
+static bool XzDecompress(OptionalByteBuffer& ret, const u8* data, size_t data_size, Error* error);
+
+static std::once_flag s_lzma_crc_table_init;
 } // namespace CompressHelpers
 
+void CompressHelpers::Init7ZCRCTables()
+{
+  std::call_once(s_lzma_crc_table_init, []() {
+    CrcGenerateTable();
+    Crc64GenerateTable();
+  });
+}
+
+const char* CompressHelpers::SZErrorToString(int res)
+{
+  // clang-format off
+  switch (res)
+  {
+  case SZ_OK: return "SZ_OK";
+  case SZ_ERROR_DATA: return "SZ_ERROR_DATA";
+  case SZ_ERROR_MEM: return "SZ_ERROR_MEM";
+  case SZ_ERROR_CRC: return "SZ_ERROR_CRC";
+  case SZ_ERROR_UNSUPPORTED: return "SZ_ERROR_UNSUPPORTED";
+  case SZ_ERROR_PARAM: return "SZ_ERROR_PARAM";
+  case SZ_ERROR_INPUT_EOF: return "SZ_ERROR_INPUT_EOF";
+  case SZ_ERROR_OUTPUT_EOF: return "SZ_ERROR_OUTPUT_EOF";
+  case SZ_ERROR_READ: return "SZ_ERROR_READ";
+  case SZ_ERROR_WRITE: return "SZ_ERROR_WRITE";
+  case SZ_ERROR_PROGRESS: return "SZ_ERROR_PROGRESS";
+  case SZ_ERROR_FAIL: return "SZ_ERROR_FAIL";
+  case SZ_ERROR_THREAD: return "SZ_ERROR_THREAD";
+  case SZ_ERROR_ARCHIVE: return "SZ_ERROR_ARCHIVE";
+  case SZ_ERROR_NO_ARCHIVE: return "SZ_ERROR_NO_ARCHIVE";
+  default: return "SZ_UNKNOWN";
+  }
+  // clang-format on
+}
+
+bool CompressHelpers::XzCompress(OptionalByteBuffer& ret, const u8* data, size_t data_size, int clevel, Error* error)
+{
+  Init7ZCRCTables();
+
+  struct MemoryInStream
+  {
+    ISeqInStream vt;
+    const u8* buffer;
+    size_t buffer_size;
+    size_t read_pos;
+  };
+  MemoryInStream mis = {{.Read = [](const ISeqInStream* p, void* buf, size_t* size) -> SRes {
+                          MemoryInStream* mis = Z7_CONTAINER_FROM_VTBL(p, MemoryInStream, vt);
+                          const size_t avail = mis->buffer_size - mis->read_pos;
+                          const size_t copy = std::min(avail, *size);
+
+                          std::memcpy(buf, &mis->buffer[mis->read_pos], copy);
+                          mis->read_pos += copy;
+                          *size = copy;
+                          return SZ_OK;
+                        }},
+                        data,
+                        data_size,
+                        0};
+
+  // Bit crap, extra copy here..
+  struct DumpOutStream
+  {
+    ISeqOutStream vt;
+    DynamicHeapArray<u8> out_data;
+    size_t out_pos;
+  };
+  DumpOutStream dos = {.vt = {.Write = [](const ISeqOutStream* p, const void* buf, size_t size) -> size_t {
+                         DumpOutStream* dos = Z7_CONTAINER_FROM_VTBL(p, DumpOutStream, vt);
+                         if ((dos->out_pos + size) > dos->out_data.size())
+                           dos->out_data.resize(std::max(dos->out_pos + size, dos->out_data.size() * 2));
+                         std::memcpy(&dos->out_data[dos->out_pos], buf, size);
+                         dos->out_pos += size;
+                         return size;
+                       }},
+                       .out_data = DynamicHeapArray<u8>(data_size / 2),
+                       .out_pos = 0};
+
+  CXzProps props;
+  XzProps_Init(&props);
+  props.lzma2Props.lzmaProps.level = std::clamp(clevel, 1, 9);
+
+  const SRes res = Xz_Encode(&dos.vt, &mis.vt, &props, nullptr);
+  if (res != SZ_OK)
+  {
+    Error::SetStringFmt(error, "Xz_Encode() failed: {} ({})", SZErrorToString(res), static_cast<int>(res));
+    return false;
+  }
+
+  dos.out_data.resize(dos.out_pos);
+  ret = OptionalByteBuffer(std::move(dos.out_data));
+  return true;
+}
+
+bool CompressHelpers::XzDecompress(OptionalByteBuffer& ret, const u8* data, size_t data_size, Error* error)
+{
+  static constexpr size_t kInputBufSize = static_cast<size_t>(1) << 18;
+
+  Init7ZCRCTables();
+
+  struct MyInStream
+  {
+    ISeekInStream vt;
+    const u8* data;
+    size_t data_size;
+    size_t data_pos;
+  };
+
+  MyInStream mis = {.vt = {.Read = [](const ISeekInStream* p, void* buf, size_t* size) -> SRes {
+                             MyInStream* mis = Z7_CONTAINER_FROM_VTBL(p, MyInStream, vt);
+                             const size_t size_to_read = *size;
+                             const size_t size_to_copy = std::min(size_to_read, mis->data_size - mis->data_pos);
+                             std::memcpy(buf, &mis->data[mis->data_pos], size_to_copy);
+                             mis->data_pos += size_to_copy;
+                             return (size_to_copy == size_to_read) ? SZ_OK : SZ_ERROR_READ;
+                           },
+                           .Seek = [](const ISeekInStream* p, Int64* pos, ESzSeek origin) -> SRes {
+                             MyInStream* mis = Z7_CONTAINER_FROM_VTBL(p, MyInStream, vt);
+                             static_assert(SZ_SEEK_CUR == SEEK_CUR && SZ_SEEK_SET == SEEK_SET &&
+                                           SZ_SEEK_END == SEEK_END);
+                             if (origin == SZ_SEEK_SET)
+                             {
+                               if (*pos < 0 || static_cast<size_t>(*pos) > mis->data_size)
+                                 return SZ_ERROR_READ;
+                               mis->data_pos = static_cast<size_t>(*pos);
+                               return SZ_OK;
+                             }
+                             else if (origin == SZ_SEEK_END)
+                             {
+                               mis->data_pos = mis->data_size;
+                               *pos = static_cast<s64>(mis->data_pos);
+                               return SZ_OK;
+                             }
+                             else if (origin == SZ_SEEK_CUR)
+                             {
+                               const s64 new_pos = static_cast<s64>(mis->data_pos) + *pos;
+                               if (new_pos < 0 || static_cast<size_t>(new_pos) > mis->data_size)
+                                 return SZ_ERROR_READ;
+                               mis->data_pos = static_cast<size_t>(new_pos);
+                               *pos = new_pos;
+                               return SZ_OK;
+                             }
+                             else
+                             {
+                               return SZ_ERROR_READ;
+                             }
+                           }},
+                    .data = data,
+                    .data_size = data_size,
+                    .data_pos = 0};
+
+  CLookToRead2 look_stream = {};
+  LookToRead2_INIT(&look_stream);
+  LookToRead2_CreateVTable(&look_stream, False);
+  look_stream.realStream = &mis.vt;
+  look_stream.bufSize = kInputBufSize;
+  look_stream.buf = static_cast<Byte*>(ISzAlloc_Alloc(&g_Alloc, kInputBufSize));
+  if (!look_stream.buf)
+  {
+    Error::SetString(error, "Failed to allocate lookahead buffer");
+    return false;
+  }
+  const ScopedGuard guard = [&look_stream]() {
+    if (look_stream.buf)
+      ISzAlloc_Free(&g_Alloc, look_stream.buf);
+  };
+
+  // Read blocks
+  CXzs xzs;
+  Xzs_Construct(&xzs);
+  const ScopedGuard xzs_guard([&xzs]() { Xzs_Free(&xzs, &g_Alloc); });
+
+  Int64 start_pos = static_cast<Int64>(data_size);
+  SRes res = Xzs_ReadBackward(&xzs, &look_stream.vt, &start_pos, nullptr, &g_Alloc);
+  if (res != SZ_OK)
+  {
+    Error::SetStringFmt(error, "Xzs_ReadBackward() failed: {} ({})", SZErrorToString(res), res);
+    return false;
+  }
+
+  const size_t num_blocks = Xzs_GetNumBlocks(&xzs);
+  if (num_blocks == 0)
+  {
+    Error::SetString(error, "Stream has no blocks.");
+    return false;
+  }
+
+  // compute output size
+  size_t stream_size = 0;
+  for (int sn = static_cast<int>(xzs.num - 1); sn >= 0; sn--)
+  {
+    const CXzStream& stream = xzs.streams[sn];
+    for (size_t bn = 0; bn < stream.numBlocks; bn++)
+    {
+      const CXzBlockSizes& block = stream.blocks[bn];
+      stream_size += block.unpackSize;
+    }
+  }
+
+  if (stream_size == 0)
+  {
+    Error::SetString(error, "Stream is empty.");
+    return false;
+  }
+
+  ByteBuffer out_buffer(stream_size);
+  size_t out_pos = 0;
+
+  CXzUnpacker unpacker = {};
+  XzUnpacker_Construct(&unpacker, &g_Alloc);
+
+  for (int sn = static_cast<int>(xzs.num - 1); sn >= 0; sn--)
+  {
+    const CXzStream& stream = xzs.streams[sn];
+    size_t src_offset = stream.startOffset + XZ_STREAM_HEADER_SIZE;
+    if (src_offset >= data_size)
+      break;
+
+    for (size_t bn = 0; bn < stream.numBlocks; bn++)
+    {
+      const CXzBlockSizes& block = stream.blocks[bn];
+
+      XzUnpacker_Init(&unpacker);
+      unpacker.streamFlags = stream.flags;
+      XzUnpacker_PrepareToRandomBlockDecoding(&unpacker);
+      XzUnpacker_SetOutBuf(&unpacker, &out_buffer[out_pos], out_buffer.size() - out_pos);
+
+      const size_t orig_compressed_size =
+        std::min<size_t>(Common::AlignUpPow2(block.totalSize, 4),
+                         static_cast<size_t>(data_size - src_offset)); // LZMA blocks are 4 byte aligned?;
+
+      SizeT block_uncompressed_size = block.unpackSize;
+      SizeT block_compressed_size = orig_compressed_size;
+
+      ECoderStatus status;
+      res = XzUnpacker_Code(&unpacker, nullptr, &block_uncompressed_size, &data[src_offset], &block_compressed_size,
+                            true, CODER_FINISH_END, &status);
+      if (res != SZ_OK || status != CODER_STATUS_FINISHED_WITH_MARK) [[unlikely]]
+      {
+        Error::SetStringFmt(error, "XzUnpacker_Code() failed: {} ({}) (status {})", SZErrorToString(res), res,
+                            static_cast<unsigned>(status));
+        return false;
+      }
+
+      if (block_compressed_size != orig_compressed_size || block_uncompressed_size != block.unpackSize)
+      {
+        WARNING_LOG("Decompress size mismatch: {}/{} vs {}/{}", block_compressed_size, block_uncompressed_size,
+                    orig_compressed_size, block.unpackSize);
+      }
+
+      out_pos += block_uncompressed_size;
+      src_offset += block_compressed_size;
+    }
+  }
+
+  if (out_pos != out_buffer.size())
+  {
+    Error::SetStringFmt(error, "Only decompressed {} of {} bytes", out_pos, out_buffer.size());
+    return false;
+  }
+
+  ret = std::move(out_buffer);
+  return true;
+}
+
 std::optional<CompressHelpers::CompressType> CompressHelpers::GetCompressType(const std::string_view path, Error* error)
 {
   const std::string_view extension = Path::GetExtension(path);
   if (StringUtil::EqualNoCase(extension, "zst"))
     return CompressType::Zstandard;
+  else if (StringUtil::EqualNoCase(extension, "xz"))
+    return CompressType::XZ;
 
   return CompressType::Uncompressed;
 }
@@ -92,7 +374,11 @@ bool CompressHelpers::DecompressHelper(CompressHelpers::OptionalByteBuffer& ret,
 
       return true;
     }
-    break;
+
+    case CompressType::XZ:
+    {
+      return XzDecompress(ret, data.data(), data.size(), error);
+    }
 
       DefaultCaseIsUnreachable()
   }
@@ -139,6 +425,11 @@ bool CompressHelpers::CompressHelper(OptionalByteBuffer& ret, CompressType type,
       return true;
     }
 
+    case CompressType::XZ:
+    {
+      return XzCompress(ret, data.data(), data.size(), clevel, error);
+    }
+
       DefaultCaseIsUnreachable()
   }
 }
diff --git a/src/util/compress_helpers.h b/src/util/compress_helpers.h
index db47224d4..798d458fc 100644
--- a/src/util/compress_helpers.h
+++ b/src/util/compress_helpers.h
@@ -15,6 +15,7 @@ enum class CompressType
 {
   Uncompressed,
   Zstandard,
+  XZ,
   Count
 };
 
@@ -44,4 +45,7 @@ bool CompressToFile(const char* path, std::span<const u8> data, int clevel = -1,
                     Error* error = nullptr);
 bool CompressToFile(CompressType type, const char* path, std::span<const u8> data, int clevel = -1,
                     bool atomic_write = true, Error* error = nullptr);
+
+const char* SZErrorToString(int res);
+
 } // namespace CompressHelpers
diff --git a/src/util/util.vcxproj b/src/util/util.vcxproj
index f8e8b2fa5..ad910df6c 100644
--- a/src/util/util.vcxproj
+++ b/src/util/util.vcxproj
@@ -217,6 +217,9 @@
     <ProjectReference Include="..\..\dep\libchdr\libchdr.vcxproj">
       <Project>{425d6c99-d1c8-43c2-b8ac-4d7b1d941017}</Project>
     </ProjectReference>
+    <ProjectReference Include="..\..\dep\lzma\lzma.vcxproj">
+      <Project>{dd944834-7899-4c1c-a4c1-064b5009d239}</Project>
+    </ProjectReference>
     <ProjectReference Include="..\..\dep\reshadefx\reshadefx.vcxproj">
       <Project>{27b8d4bb-4f01-4432-bc14-9bf6ca458eee}</Project>
     </ProjectReference>
@@ -250,7 +253,7 @@
   <Import Project="util.props" />
   <ItemDefinitionGroup>
     <ClCompile>
-      <AdditionalIncludeDirectories>%(AdditionalIncludeDirectories);$(SolutionDir)dep\reshadefx\include</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>%(AdditionalIncludeDirectories);$(SolutionDir)dep\reshadefx\include;$(SolutionDir)dep\lzma\include</AdditionalIncludeDirectories>
       <ObjectFileName>$(IntDir)/%(RelativeDir)/</ObjectFileName>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <PrecompiledHeaderFile>pch.h</PrecompiledHeaderFile>