diff --git a/bpython/curtsiesfrontend/repl.py b/bpython/curtsiesfrontend/repl.py
index a29b350a..20188f50 100644
--- a/bpython/curtsiesfrontend/repl.py
+++ b/bpython/curtsiesfrontend/repl.py
@@ -179,12 +179,18 @@ def add_input_character(self, e: str) -> None:
         )
         self.cursor_offset += 1
 
-    def readline(self):
+    def readline(self, size: int = -1) -> Union[str, Any]:
+        if not isinstance(size, int):
+            raise TypeError(
+                f"'{type(size).__name__}' object cannot be interpreted as an integer"
+            )
+        elif size == 0:
+            return ""
         self.has_focus = True
         self.repl.send_to_stdin(self.current_line)
         value = self.coderunner.request_from_main_context()
         self.readline_results.append(value)
-        return value
+        return value if size <= -1 else value[:size]
 
     def readlines(self, size=-1):
         return list(iter(self.readline, ""))