“Substantial Motivating Reason” Explained: What California Employers Must Know
Introduction
When making personnel decisions, California employers must be cautious about the reasons behind them—especially when those reasons touch on an employee’s protected status. Under the Fair Employment and Housing Act (FEHA), plaintiffs don’t need to prove that discrimination or retaliation was the only reason for termination, demotion, or other adverse employment actions. Instead, courts apply the standard of whether the protected trait or activity was a “substantial motivating reason.”
This standard, established by the California Supreme Court and applied in discrimination and retaliation cases, sets the evidentiary bar for causation in employment litigation. If you’re a business owner, understanding this threshold is critical both for compliance and for defending claims.
What Does “Substantial Motivating Reason” Mean?
A substantial motivating reason is one that:
Actually contributed to the adverse action taken against the employee.
Was more than a remote or trivial reason.
Does not need to be the sole or exclusive reason.
In other words, if discrimination, retaliation, or another unlawful motive significantly influenced the decision—even alongside legitimate business reasons—liability can follow.
Example: If an employee is terminated for “performance issues,” but their age, pregnancy status, or prior complaint about harassment strongly factored into the decision, a court may find those protected traits or activities were a substantial motivating reason.
How Courts Apply the Standard
California courts have clarified the “substantial motivating reason” through key rulings:
The employee must show a causal connection between the protected status (such as disability, religion, age, or military service) and the adverse employment action. It is not enough for bias to exist in the workplace without affecting the actual decision. (Mixon v. FEHC (1987) 192 Cal.App.3d 1306, 1319).
A plaintiff need not show discrimination or retaliation was the sole motivation. It is sufficient if the unlawful motive was significant and consequential, even if other legitimate reasons also supported the decision. (Clark v. Claremont Univ. Center (1992) 6 Cal.App.4th 639, 665).
The California Supreme Court in Harris v. City of Santa Monica (2013) 56 Cal.4th 203, 229–32, stressed that requiring proof discrimination was a “substantial motivating reason” prevents liability for stray remarks or trivial biases, while ensuring employers remain accountable when unlawful factors meaningfully influence decisions.
What an Employee Must Prove
To succeed in a discrimination or retaliation claim under this standard, an employee generally must demonstrate:
They were employed by you.
They suffered an adverse employment action (e.g., termination, demotion, denied promotion, discipline).
Their protected status (or protected activity like reporting hostility or requesting accommodation) was a substantial motivating reason for your action.
They were harmed as a result.
Your conduct was a substantial factor in causing that harm.
(Gov’t Code § 12940(a); CACI Nos. 2500, 2505, 2507).
Employer Liability and Consequences
If a court or jury finds that discrimination or retaliation was a substantial motivating reason:
The employer is liable under FEHA, even if other factors also played a role.
Remedies can include compensation for lost wages, benefits, emotional distress, reinstatement, promotion, or hiring, along with attorney’s fees. (Gov’t Code § 12965(c)).
Mixed-motive rule (Harris): If the employer proves it would have made the same decision even without the discriminatory motive, full damages such as backpay, reinstatement, or promotion may not be awarded. However, the employee may still obtain declaratory relief, injunctive relief, and attorney’s fees, reflecting California’s commitment to deterrence and accountability. (Harris, 56 Cal.4th at 234).
Best Practices for Employers
To reduce exposure, California employers should:
Document legitimate reasons: Maintain clear, contemporaneous records of performance issues, disciplinary actions, and business needs that drive employment decisions.
Train managers: Ensure supervisors understand that even partial reliance on discriminatory motives can create liability.
Avoid reliance on “stray remarks”: Offhand comments by leadership tied to protected traits may become powerful evidence if connected to an adverse action.
Ensure consistent application of policies: Treat similarly situated employees alike to avoid claims of disparate treatment.
Seek legal guidance: Before terminating or disciplining employees in sensitive categories, consult with employment counsel (e.g., myself).
Bottom Line
The “substantial motivating reason” standard is a pivotal concept in California employment law. For business owners, it serves as a reminder that decisions must be firmly grounded in legitimate business reasons—not influenced by stereotypes, bias, or retaliation. Even if lawful reasons exist, once unlawful motives meaningfully influence the decision, liability may follow.
By focusing on documentation, consistent practices, and training, businesses can avoid risk and foster fairness—while ensuring compliance with California law.
Citations
Cal. Gov’t Code § 12940(a); 42 U.S.C. § 2000e-2(m); Cal. Code Regs., tit. 2, § 11009(c); Guz v. Bechtel Nat’l Inc., 24 Cal.4th 317 (2000); Mixon v. FEHC, 192 Cal.App.3d 1306 (1987); Clark v. Claremont Univ. Ctr., 6 Cal.App.4th 639 (1992); McDonald v. Santa Fe Trail Transp. Co., 427 U.S. 273 (1976); Harris v. City of Santa Monica, 56 Cal.4th 203 (2013); Alamo v. Practice Mgmt. Info. Corp., 219 Cal.App.4th 466 (2013); CACI No. 2507.
