diff --git a/lib/reline/config.rb b/lib/reline/config.rb
index e0fc37fc68..d437156650 100644
--- a/lib/reline/config.rb
+++ b/lib/reline/config.rb
@@ -177,6 +177,11 @@ def read_lines(lines, file = nil)
     if_stack = []
 
     lines.each_with_index do |line, no|
+      # Even after encoding conversion, we need to verify the encoding is valid
+      # as some invalid byte sequences might pass through the conversion.
+      unless line.valid_encoding?
+        raise InvalidInputrc, "#{file}:#{no + 1}: can't be converted to the locale #{Reline.encoding_system_needs.name}"
+      end
       next if line.match(/\A\s*#/)
 
       no += 1
diff --git a/test/reline/test_config.rb b/test/reline/test_config.rb
index 3c9094eece..ff3e121ab0 100644
--- a/test/reline/test_config.rb
+++ b/test/reline/test_config.rb
@@ -613,4 +613,21 @@ def test_reload
     @config.reload
     assert_equal '@', @config.emacs_mode_string
   end
+
+  def test_invalid_byte_sequence_inputrc
+    lines = [
+      "set vi-cmd-mode-string\n",
+      "$if Ruby\n",
+      "  \"\C-a\": \"Ruby\"\n",
+      "$else \"\xFF\"\n".dup.force_encoding(Reline.encoding_system_needs), # Invalid byte sequence
+      "  \"\C-b\": \"NotRuby\"\n",
+      "$endif\n"
+    ]
+
+    e = assert_raise(Reline::Config::InvalidInputrc) do
+      @config.read_lines(lines, "INPUTRC")
+    end
+
+    assert_equal "INPUTRC:4: can't be converted to the locale #{Reline.encoding_system_needs}", e.message
+  end
 end