After petitioner borough fired respondent Guarnieri as its police chief, he filed a union grievance that led to his reinstatement. When the borough council later issued directives instructing Guarnieri how to perform his duties, he filed a second grievance, and an arbitrator ordered that some of the directives be modified or withdrawn. Guarnieri then filed this suit under 42 U. S. C. §1983, alleging that the directives were issued in retaliation for the filing of his first grievance, thereby violating his First Amendment “right… to petition the Government for a redress of grievances”; he later amended his complaint to allege that the council also violated the Petition Clause by denying his request for overtime pay in retaliation for his having filed the §1983 suit. The District Court instructed the jury, inter alia, that the suit and the grievances were constitutionally protected activity, and the jury found for Guarnieri. Affirming the compensatory damages award, the Third Circuit held that a public employee who has petitioned the government through a formal mechanism such as the filing of a lawsuit or grievance is protected under the Petition Clause from retaliation for that activity, even if the petition concerns a matter of solely private concern. In so ruling, the court rejected the view of every other Circuit to have considered the issue that, to be protected, the petition must address a matter of public concern.

Held: A government employer’s allegedly retaliatory actions against an employee do not give rise to liability under the Petition Clause unless the employee’s petition relates to a matter of public concern. The Third Circuit’s conclusion that the public concern test does not limit public employees’ Petition Clause claims is incorrect. Pp. 4–19.