(a) Persons having only a joint interest in the subject matter of an action must be joined on the same side as plaintiffs or defendants.
Rule 2227.Compulsory joinder.
Adopted June 7, 1940 · Last amended April 12, 1999 · Last verified June 30, 2026
In one sentenceRule 2227 requires persons who have only a joint interest in the subject of an action to be joined on the same side, and addresses what happens when one will not join.
Full Text of Rule 2227
(b) If a person who must be joined as a plaintiff refuses to join, he or she shall, in a proper case, be made a defendant or an involuntary plaintiff when the substantive law permits such involuntary joinder.
Plain-English Summary
Some claims cannot be litigated piecemeal. This rule requires persons who have only a joint interest in the subject matter of an action to be joined on the same side — as plaintiffs or defendants — and addresses how to proceed when a necessary party will not voluntarily join. Compulsory joinder keeps the court from deciding a joint right without everyone who shares it.
Frequently Asked Questions
When must parties be joined to a lawsuit?
Persons with only a joint interest in the subject matter must be joined on the same side.
Amendment History
The provisions of this Rule 2227 adopted June 7, 1940, effective February 5, 1941; amended April 18, 1975, effective immediately, 5 Pa.B. 1820; amended April 12, 1999, effective July 1, 1999, 29 Pa.B. 2274. Immediately preceding text appears at serial page (190595).
Source & verification. Rule text, the Official Note, and the amendment
history are reproduced verbatim from the Pennsylvania Code, Title 231, the official compilation
of rules adopted by the Supreme Court of Pennsylvania. Last verified June 30, 2026. ·
Official text
Also known as: compulsory joindernecessary party joinderjoint interest joinder