diff --git a/src/BUILD.bazel b/src/BUILD.bazel
index b447bf4..f4d0c69 100644
--- a/src/BUILD.bazel
+++ b/src/BUILD.bazel
@@ -6,3 +6,19 @@ cc_library(
     name = "decompress",
     hdrs = ["decompress.hpp"],
 )
+
+cc_library(
+    name = "gunzip",
+    srcs = ["gunzip.cpp"],
+    hdrs = ["gunzip.hpp"],
+    deps = ["//huffman"],
+)
+
+cc_binary(
+    name = "gunzip_main",
+    srcs = ["gunzip_main.cpp"],
+    deps = [
+        ":decompress",
+        ":gunzip",
+    ],
+)
diff --git a/src/gunzip.cpp b/src/gunzip.cpp
new file mode 100644
index 0000000..f08c4d6
--- /dev/null
+++ b/src/gunzip.cpp
@@ -0,0 +1,9 @@
+#include "gunzip.hpp"
+
+namespace starflate {
+auto gunzip(std::istream& in, std::ostream& out) -> GunzipError
+{
+  // TODO: implement
+  return GunzipError::NoError;
+}
+}  // namespace starflate
diff --git a/src/gunzip.hpp b/src/gunzip.hpp
new file mode 100644
index 0000000..6442fb5
--- /dev/null
+++ b/src/gunzip.hpp
@@ -0,0 +1,12 @@
+#include <cstdint>
+#include <istream>
+#include <ostream>
+
+namespace starflate {
+enum class GunzipError : std::uint8_t
+{
+  NoError,
+  Error,
+};
+auto gunzip(std::istream& in, std::ostream& out) -> GunzipError;
+}  // namespace starflate
diff --git a/src/gunzip_main.cpp b/src/gunzip_main.cpp
new file mode 100644
index 0000000..f77c90a
--- /dev/null
+++ b/src/gunzip_main.cpp
@@ -0,0 +1,76 @@
+#include "gunzip.hpp"
+
+#include <cstring>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <ostream>
+
+// NOLINTBEGIN(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+
+auto usage(const char* program) -> int
+{
+  std::cerr << "Usage: " << program << "[OPTIONS] <filename>" << std::endl;
+  std::cerr << "OPTIONS:" << std::endl;
+  std::cerr
+      << "\n\t-c --stdout --to-stdout\n\t\tWrite to standard output"
+      << std::endl;
+  return EXIT_FAILURE;
+}
+
+auto decompressed_path(const std::filesystem::path& in_path)
+    -> std::filesystem::path
+{
+  std::filesystem::path res{in_path};
+  if (in_path.extension() == ".gz") {
+    res.replace_extension();
+  } else {
+    res += ".decompressed";
+  }
+  return res;
+}
+
+auto main(const int argc, const char* argv[]) -> int
+{
+  if (argc < 2 || argc > 3) {
+    return usage(argv[0]);
+  }
+
+  std::filesystem::path in_path;
+  bool to_stdout{};
+  std::ofstream out_file;
+  if (argc == 3) {
+    const auto option = argv[1];
+    // NOLINTBEGIN(readability-magic-numbers)
+    if (strncmp(option, "-c", 2) != 0 && strncmp(option, "--stdout", 8) != 0 &&
+        strncmp(option, "--to-stdout", 11) != 0) {
+      // NOLINTEND(readability-magic-numbers)
+      return usage(argv[0]);
+    }
+    in_path = argv[2];
+    to_stdout = true;
+  } else {
+    in_path = argv[1];
+    std::filesystem::path out_path{decompressed_path(in_path)};
+    out_file.open(out_path, std::ios::binary);
+    if (!out_file.is_open()) {
+      std::cerr << "Failed to open " << out_path << " for writing" << std::endl;
+      return EXIT_FAILURE;
+    }
+  }
+  // NOLINTEND(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+  auto& out = to_stdout ? std::cout : out_file;
+
+  std::ifstream in{in_path, std::ios::binary};
+  if (!in.is_open()) {
+    std::cerr << "Failed to open " << in_path << " for reading" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  const auto err = starflate::gunzip(in, out);
+  if (err != starflate::GunzipError::NoError) {
+    std::cerr << "Error: " << static_cast<int>(err) << std::endl;
+    return EXIT_FAILURE;
+  }
+  return EXIT_SUCCESS;
+}