WASHINGTON — In a decision that could impact companies’ hiring practices, the Supreme Court ruled Monday against Abercrombie & Fitch Co. in a case involving a Muslim woman who alleged she was denied a position because she wore a head scarf to a job interview.

In an 8-to-1 ruling, the High Court said a job applicant or employee must only show a need for religious accommodation to prevail in a “disparate treatment claim,” or intentional discrimination, and rejected A&F’s argument and an appeals court decision that an employer needed to have actual knowledge of a religious conflict through a direct request for accommodation from the job applicant.

The court reversed and remanded the case back to the 10th U.S. Circuit Court of Appeals for further consideration. While the case has not been resolved, the Supreme Court’s decision on a central legal question in the case could have significant implications for hiring practices for U.S. firms.

At the heart of the case was whether an employee or job applicant bears the burden of requesting a religious accommodation or whether an employer must have “actual knowledge” about a potential religious conflict before making employment decisions.

“Abercrombie’s primary argument is that an applicant cannot show disparate treatment without first showing that an employer has ‘actual knowledge’ of the applicant’s need for an accommodation,” wrote Supreme Court Justice Antonin Scalia in the majority opinion. “We disagree. Instead, an applicant need only show that his need for an accommodation was a motivating factor in the employer’s decision.”

The court said an employer may violate a Civil Rights Era law with “no more than an unsubstantiated suspicion that accommodation would be needed.”

“The rule for disparate-treatment claims based on a failure to accommodate a religious practice is straightforward: An employer may not make an applicant’s religious practice, confirmed or otherwise, a factor in employment decisions,” Scalia wrote.

The decision was also a victory for the Equal Employment Opportunity Commission, which brought the case against Abercrombie in 2009 on behalf of then-17-year-old Samantha Elauf, who, in 2008, was denied a sales associate position at an Abercrombie Kids store in Tulsa, Okla.

“At its root, this case is about defending the quintessentially American principles of religious freedom and tolerance,” said David Lopez, EEOC general counsel. “This decision is a victory for our increasingly diverse society and we applaud Samantha Elauf’s courage and tenacity in pursuing this matter.”

Elauf wore a black head scarf, or hijab, to the job interview, but did not request a religious accommodation for wearing the scarf if she got the job. Islamic practice often requires post-adolescent Muslim women to wear a head scarf when in the presence of adult males outside of their immediate family.

Justice Samuel Alito said in a concurring opinion that there is “sufficient evidence” in the court record “to support a finding that Abercrombie’s decision-makers knew that Elauf was Muslim and that she wore the headscarf for a religious reason.”

A&F argued that it denied her job application based on the grounds that wearing a scarf violated its “look policy,” which requires sales associates to wear clothes similar to those sold in its stores.

The U.S. District Court for the Northern District of Oklahoma granted summary judgment to the EEOC in 2011 and allowed a jury trial that awarded Elauf $20,000 in damages. But the 10th U.S. Circuit Court of Appeals reversed the lower court’s decision in favor of A&F in 2013.

“I was a teenager who loved fashion and was eager to work for Abercrombie & Fitch,” said Elauf, as part of the EEOC’s statement. “Observance of my faith should not have prevented me from getting a job. I am glad that I stood up for my rights, and happy that the EEOC was there for me and took my complaint to the courts. I am grateful to the Supreme Court for today’s decision and hope that other people realize that this type of discrimination is wrong and the EEOC is there to help.”

An A&F spokeswoman in an e-mailed statement said: “While the Supreme Court reversed the Tenth Circuit decision, it did not determine that A&F discriminated against Ms. Elauf. We will determine our next steps in the litigation, which the Supreme Court remanded for further consideration.

“A&F remains focused on ensuring the company has an open-minded and tolerant workplace environment for all current and future store associates,” she added. “We have made significant enhancements to our store associate policies, including the replacement of the ‘look policy’ with a new dress code that allows associates to be more individualistic, changed our hiring practices to not consider attractiveness, and changed store associates’ titles from ‘Model’ to ‘Brand Representative’ to align with their new customer focus. This case relates to events occurring in 2008. A&F has a longstanding commitment to diversity and inclusion, and consistent with the law, has granted numerous religious accommodations when requested, including hijabs.”

Business groups said the ruling could have far-reaching implications for employers, particularly small businesses. The National Federation of Independent Business said the ruling will force all employers to make assumptions about job applicants’ religion, a move that is certain to “trigger lawsuits.”

“Shifting this burden to employers sets an unclear and confusing standard, making business owners extremely vulnerable to inevitable discrimination lawsuits,” said Karen Harned, director of the NFIB Small Business Legal Center. “Whether employers ask an applicant about religious needs or not, there is a good chance they will be sued.”

Clarence Thomas partly concurred with the majority opinion, and partly dissented, keeping the ruling from being unanimous. In sending the case back to the 10th Circuit Court of Appeals, Alito said that court can “consider whether there is sufficient evidence to support summary judgment in favor of the EEOC on the question of Abercrombie’s knowledge. The 10th Circuit will also be required to address Abercrombie’s claim that it could not have accommodated Elauf ’s wearing the headscarf on the job without undue hardship.”