The Americans with Disabilities Act has several sections among other things is addresses public accessibility and employment discrimination. The ADA prohibits covered entities from discrimination against qualified individuals with disabilities.

For purposes of the ADA in employment matters the term disabilities means that the impairment of the individual is one that substantially limits a major life activity. Moderate limitations on major life activities are insufficient to qualify the individual for coverage, this probably because almost everyone has some sort of limitation. Substantially has been interpreted to mean to a large degree and more than trivial. Impairments that have a minor impact in everyday activities that are basically a minor interference is insufficient for ADA protection to apply. There is no set rule or bright line as to what constitutes a major limitation, each case has to be viewed individually and the determination of ADA applicability has to be on a case by case basis.

The EEOC provides some guidelines in that they define substantially limiting as unable to perform a major life activity that the average person in the general population can perform or as a significant restriction. Generally speaking a person in a wheel chair would be covered, since walking is considered a major life activity that cannot be performed by such a claimant. For other claimants three factors are considered:
(1) the nature and severity of the impairment;
(2) the duration or expected duration of the impairment;
(3) and the actual or expected permanent or long term impact resulting from the impairment.

For purposes of the ADA the phrase covered entities includes an employer, employment agency, and labor organization. A labor organization and employment agency is defined as having the same definition as described under the Civil Rights Act of 1964, Title VII. The term employer means an employer which includes a natural person or a legal entity that is engaged in an industry affecting commerce with 15 or more employees on each working day in each of 20 or more calendar weeks in the current or preceding year.

There are a few exempt employers as follows:
(1) The federal government including corporations wholly owned by the federal government;
(2) Native American Tribes, which are generally exempt from almost all state laws and federal law;
(3) A bona fide, private membership club, exempt from income tax as nonprofit organization.

Religious organizations may discriminate to some extent. The religious organization may give employment preference to its own members and may require that all employees, including those with disabilities adhere to the religious beliefs of the religious organization and to conform to the its religious tenets. The religious organization cannot discriminate solely on the basis of the individuals disability.

To prove a case of discrimination the claimant has to show that:
(1) the claimant is an employee or prospective employee of the employer or prospective employer;
(2) the claimant has to prove a disability after taking into consideration corrective measures such as medication;
(3) the claimant has to prove discrimination;
(4) the claimant has to prove a causal connection between an adverse action against the claimant and the discriminatory conduct;
(5) and the claimant has to prove damages.

Under California Law the same basic rules apply. In California a claimant does not need to have a disability to be able to make a claim. If the employer terminates the employee or refuses to hire, because the employer believes the person to be disabled that is sufficient to make a claim, even if the employee does not have a disability. The act of discriminating because of a perceived disability is sufficient.

California Statutes specifically state that the employer is not prohibited from refusing to hire or from discharging an employee with a physical or mental disability, where the employee, is unable to perform his or her essential duties even with reasonable accommodations, or the employee cannot perform those duties in a manner that would not endanger his or her health or safety or the health or safety of others even with reasonable accommodations.

An employer, labor organization, employment agency, apprenticeship training program or any training program leading to employment, or any other person, is also prohibited to harass an employee, an applicant, or a person providing services pursuant to a contract. California law is broad enough that it extends coverage to persons providing services pursuant to a contract. Harassment of an employee, an applicant, or a person providing services pursuant to a contract by an employee, other than an agent or supervisor, shall be unlawful if the entity, or its agents or supervisors, knows or should have known of this conduct and fails to take immediate and appropriate corrective action.

"A person providing services pursuant to a contract" means a person who meets all of the
following criteria:
(1) The person has the right to control the performance of the contract for services and discretion as to the manner of performance;
(2) The person is customarily engaged in an independently established business;
(3) The person has control over the time and place the work is performed, supplies the tools and instruments used in the work, and performs work that requires a particular skill not ordinarily used in the course of the employer's work.

A claim for harassment can be brought under California law against any employer, regardless of how many employees it employs. Only one employee is required or regularly receiving the services of one or more persons providing services pursuant to a contract, or any person acting as an agent of an employer, directly or indirectly, the state, or any political or civil subdivision of the state, and cities.