diff --git a/middleman-more/lib/middleman-more/extensions/gzip.rb b/middleman-more/lib/middleman-more/extensions/gzip.rb
index 07ae563b..6e574148 100644
--- a/middleman-more/lib/middleman-more/extensions/gzip.rb
+++ b/middleman-more/lib/middleman-more/extensions/gzip.rb
@@ -39,12 +39,26 @@ module Middleman::Extensions
       def gzip_file(path, builder)
         input_file = File.open(path, 'r').read
         output_filename = path + '.gz'
+        input_file_time = File.mtime(path)
+
+        # Check if the right file's already there
+        if File.exist?(output_filename) && File.mtime(output_filename) == input_file_time
+          return
+        end
+
         File.open(output_filename, 'w') do |f|
           gz = Zlib::GzipWriter.new(f, Zlib::BEST_COMPRESSION)
+          gz.mtime = input_file_time.to_i
           gz.write input_file
           gz.close
         end
 
+        # Make the file times match, both for Nginx's gzip_static extension
+        # and so we can ID existing files. Also, so even if the GZ files are
+        # wiped out by build --clean and recreated, we won't rsync them over
+        # again because they'll end up with the same mtime.
+        File.utime(File.atime(output_filename), input_file_time, output_filename)
+
         old_size = File.size(path)
         new_size = File.size(output_filename)