diff --git a/lib/rdf/util/file.rb b/lib/rdf/util/file.rb
index 4264dac7..a4b8e4c8 100644
--- a/lib/rdf/util/file.rb
+++ b/lib/rdf/util/file.rb
@@ -319,6 +319,12 @@ def self.open_file(filename_or_url, proxy: nil, headers: {}, verify_none: false,
           url_no_frag_or_query.query = nil
           url_no_frag_or_query.fragment = nil
           options[:encoding] ||= Encoding::UTF_8
+
+          # Normalize a file scheme further
+          if url_no_frag_or_query.scheme == 'file'
+            url_no_frag_or_query = "file:///#{url_no_frag_or_query.path}"
+          end
+
           Kernel.open(url_no_frag_or_query, "r", **options) do |file|
             document_options = {
               base_uri:     filename_or_url.to_s,