In a unanimous decision, the Supreme Court of the United States held that under Title VII of the Civil Rights Act of 1964 an employer that denies a religious accommodation must show that granting the accommodation would impose “substantial increased costs in relation to the conduct of its particular business.” This marked a key clarification of the standard for when an employer may refuse accommodation of an employee’s religious practice.

Prior precedent—from Trans World Airlines, Inc. v. Hardison (1977)—held that an employer could refuse a religious accommodation if it would incur more than a de minimis cost. The Court in Groff found that this “de minimis” standard was too weak to reflect the statutory standard of “undue hardship” and that employers must now meet the higher threshold of showing substantial interference.

The case arose from the employment of Gerald Groff, a mail-carrier for the United States Postal Service, who refused to work Sunday shifts due to his religious observance of the Sabbath. The USPS disciplined him, and lower courts denied his accommodation claim under the Hardison standard. The Supreme Court remanded the case with guidance under the new “substantial increased cost” test.

The ruling has broad implications for employment law and religious accommodation. Employers must now engage in a more careful, fact-specific analysis of accommodation requests—considering size, nature, and operating cost of the business, and examining alternatives and impact on the employer’s operations. Costs or worker inconvenience that might have been sufficient under the old “de minimis” standard will no longer automatically justify denial.