diff --git a/lib/pry/pry_class.rb b/lib/pry/pry_class.rb
index 86220f66..f16aa766 100644
--- a/lib/pry/pry_class.rb
+++ b/lib/pry/pry_class.rb
@@ -25,10 +25,6 @@ class Pry
     #   Pry.custom_completions = proc { Dir.entries('.') }
     attr_accessor :custom_completions
 
-    # Value returned by last executed Pry command.
-    # @return [Object] The command value
-    attr_accessor :cmd_ret_value
-
     # @return [Fixnum] The current input line.
     attr_accessor :current_line
 
diff --git a/lib/pry/pry_instance.rb b/lib/pry/pry_instance.rb
index f05d3b23..4cd778dc 100644
--- a/lib/pry/pry_instance.rb
+++ b/lib/pry/pry_instance.rb
@@ -278,7 +278,7 @@ class Pry
   # @param [String] val The input string.
   # @return [Boolean] Whether the input is null.
   def null_input?(val)
-    val.empty? && !Pry.cmd_ret_value
+    val.empty? && !Thread.current[:__pry_cmd_ret_value__]
   end
 
   # Read a line of input and check for ^d, also determine prompt to use.
@@ -306,10 +306,10 @@ class Pry
   # @param [String] eval_string The cumulative lines of input.
   # @param [Binding] target The target of the Pry session.
   def process_line(val, eval_string, target)
-    Pry.cmd_ret_value = @command_processor.process_commands(val, eval_string, target)
+    Thread.current[:__pry_cmd_ret_value__] = @command_processor.process_commands(val, eval_string, target)
 
-    if Pry.cmd_ret_value
-      eval_string << "Pry.cmd_ret_value\n"
+    if Thread.current[:__pry_cmd_ret_value__]
+      eval_string << "Thread.current[:__pry_cmd_ret_value__]\n"
     else
       # only commands (with no ret_value) should have an empty `val` so this ignores their result
       eval_string << "#{val.rstrip}\n" if !val.empty?