diff --git a/include/boost/pfr/detail/fields_count.hpp b/include/boost/pfr/detail/fields_count.hpp
index 625159a..878d64f 100644
--- a/include/boost/pfr/detail/fields_count.hpp
+++ b/include/boost/pfr/detail/fields_count.hpp
@@ -221,7 +221,7 @@ constexpr std::size_t fields_count_compiler_limitation_next(std::size_t n) noexc
 ///////////////////// Fields count upper bound based on sizeof(T)
 template <class T>
 constexpr std::size_t fields_count_upper_bound_loose() noexcept {
-    return sizeof(T) * std::numeric_limits<unsigned char>::digits;
+    return sizeof(T) * std::numeric_limits<unsigned char>::digits + 1 /* +1 for "Arrays of Length Zero" extension */;
 }
 
 ///////////////////// Fields count binary search.
diff --git a/test/core/run/zero_size_array.cpp b/test/core/run/zero_size_array.cpp
new file mode 100644
index 0000000..a258d5e
--- /dev/null
+++ b/test/core/run/zero_size_array.cpp
@@ -0,0 +1,33 @@
+// Copyright (c) 2025-2025 Antony Polukhin
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// Test that PFR works with GCCs "Arrays of Length Zero" extension
+
+#include <boost/pfr/core.hpp>
+
+#include <tuple>
+
+#if defined(__GNUC__) && (BOOST_PFR_USE_LOOPHOLE || BOOST_PFR_USE_CPP17)
+struct zero_array {
+    char data[0];
+};
+
+struct aggr {
+    zero_array a;
+};
+
+static_assert(sizeof(zero_array) == 0);
+static_assert(sizeof(aggr) == 0);
+
+int main() {
+    aggr a;
+    const auto result = boost::pfr::structure_tie(a);
+    static_assert(std::tuple_size<decltype(result)>::value == 1);
+    return sizeof(std::get<0>(result).data);
+}
+#else
+int main() {}
+#endif
+