diff --git a/include/spdlog/details/os-inl.h b/include/spdlog/details/os-inl.h
index 87c8c5a0..c9d0642f 100644
--- a/include/spdlog/details/os-inl.h
+++ b/include/spdlog/details/os-inl.h
@@ -459,6 +459,41 @@ SPDLOG_INLINE void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target)
 
     throw_spdlog_ex(fmt::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
 }
+
+SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, memory_buf_t &target)
+{
+    if (str.size() > static_cast<size_t>((std::numeric_limits<int>::max)()))
+    {
+        throw_spdlog_ex("UTF-8 string is too big to be converted to UTF-16");
+    }
+
+    int str_size = static_cast<int>(str.size());
+    if (str_size == 0)
+    {
+        target.resize(0);
+        return;
+    }
+
+    int result_size = static_cast<int>(target.capacity());
+    if ((str_size + 1) * 2 < result_size)
+    {
+        result_size = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size, NULL, 0);
+    }
+
+    if (result_size > 0)
+    {
+        target.resize(result_size);
+        result_size = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size, (LPWSTR)target.data(), result_size);
+
+        if (result_size > 0)
+        {
+            target.resize(result_size);
+            return;
+        }
+    }
+
+    throw_spdlog_ex(fmt::format("MultiByteToWideChar failed. Last error: {}", ::GetLastError()));
+}
 #endif // (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
 
 // return true on success
diff --git a/include/spdlog/details/os.h b/include/spdlog/details/os.h
index 243a4fb8..88f13dbe 100644
--- a/include/spdlog/details/os.h
+++ b/include/spdlog/details/os.h
@@ -85,6 +85,8 @@ SPDLOG_API bool in_terminal(FILE *file) SPDLOG_NOEXCEPT;
 
 #if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
 SPDLOG_API void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target);
+
+SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, memory_buf_t &target);
 #endif
 
 // Return directory name from given path or empty string
diff --git a/include/spdlog/sinks/win_eventlog_sink.h b/include/spdlog/sinks/win_eventlog_sink.h
index 384fa9eb..f154c55a 100644
--- a/include/spdlog/sinks/win_eventlog_sink.h
+++ b/include/spdlog/sinks/win_eventlog_sink.h
@@ -57,7 +57,7 @@ struct win32_error : public spdlog_ex
 
         LPSTR format_message_result{};
         auto format_message_succeeded =
-            ::FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr,
+            ::FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr,
                 error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR)&format_message_result, 0, nullptr);
 
         if (format_message_succeeded && format_message_result)
@@ -203,7 +203,7 @@ private:
     {
         if (!hEventLog_)
         {
-            hEventLog_ = ::RegisterEventSource(nullptr, source_.c_str());
+            hEventLog_ = ::RegisterEventSourceA(nullptr, source_.c_str());
             if (!hEventLog_ || hEventLog_ == (HANDLE)ERROR_ACCESS_DENIED)
             {
                 SPDLOG_THROW(internal::win32_error("RegisterEventSource"));
@@ -218,18 +218,41 @@ protected:
     {
         using namespace internal;
 
+        bool succeeded;
         memory_buf_t formatted;
         base_sink<Mutex>::formatter_->format(msg, formatted);
         formatted.push_back('\0');
-        LPCSTR lp_str = static_cast<LPCSTR>(formatted.data());
 
-        auto succeeded = ::ReportEvent(event_log_handle(), eventlog::get_event_type(msg), eventlog::get_event_category(msg), event_id_,
-            current_user_sid_.as_sid(), 1, 0, &lp_str, nullptr);
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+        try
+        {
+            memory_buf_t buf;
+            details::os::utf8_to_wstrbuf(string_view_t(formatted.data(), formatted.size()), buf);
+
+            LPCWSTR lp_wstr = reinterpret_cast<LPCWSTR>(buf.data());
+            succeeded = ::ReportEventW(event_log_handle(), eventlog::get_event_type(msg), eventlog::get_event_category(msg), event_id_,
+                current_user_sid_.as_sid(), 1, 0, &lp_wstr, nullptr);
+
+            if (!succeeded)
+            {
+                SPDLOG_THROW(win32_error("ReportEvent"));
+            }
+        }
+        catch (...)
+        {
+            // WCHAR string conversion can fail and if it does, we shouldn't call to report event function.
+        }
+#else
+        LPCSTR lp_str = reinterpret_cast<LPCSTR>(formatted.data());
+
+        succeeded = ::ReportEventA(event_log_handle(), eventlog::get_event_type(msg), eventlog::get_event_category(msg), event_id_,
+                current_user_sid_.as_sid(), 1, 0, &lp_str, nullptr);
 
         if (!succeeded)
         {
             SPDLOG_THROW(win32_error("ReportEvent"));
         }
+#endif
     }
 
     void flush_() override {}