Under Philippine labor law, the termination of employment by the employer is strictly regulated to safeguard the constitutionally enshrined right to security of tenure. This right is central in the Labor Code of the Philippines, as well as in a vast body of jurisprudence and Department of Labor and Employment (DOLE) regulations. Generally, an employer may only dismiss an employee for causes expressly allowed by law and must faithfully observe proper procedural due process. Below is a comprehensive, meticulous overview of the foundational principles and requirements governing termination by the employer, focusing on the general rules before delving into the specifics of just and authorized causes.

1. Constitutional and Statutory Basis

Security of Tenure: Article XIII, Section 3 of the 1987 Philippine Constitution enshrines the principle that workers shall be entitled to security of tenure. This is echoed in Article 294 (formerly Article 279) of the Labor Code, which affirms that employees shall not be terminated except for just or authorized causes as provided by law.
Labor Code Provisions: The primary statutory framework governing termination is found in Book VI, Title I of the Labor Code of the Philippines (Presidential Decree No. 442, as amended). The Code’s provisions and implementing rules, along with Supreme Court decisions, set out the conditions, processes, and remedies related to the termination of employment.

2. Security of Tenure and Limited Grounds for Termination

The foundational principle is that employees, once regularized or deemed regular, have a property right in their employment. Employers may not terminate such employment at will, unlike in many “at-will” jurisdictions.
Only causes recognized by law can justify dismissal. These fall into two main categories:
a) Just Causes (attributable to the employee’s own acts or omissions, such as serious misconduct or willful disobedience)
b) Authorized Causes (arising from legitimate business reasons, such as redundancy, retrenchment, or closure)

3. Burden of Proof on the Employer

When an employer terminates an employee, it is the employer who bears the burden of proving that the dismissal was for a lawful cause and that due process was observed.
In the absence of a valid and legal ground, the termination is deemed illegal, entitling the employee to statutory remedies such as reinstatement and backwages.

4. The Importance of Due Process

Substantive Due Process: Refers to the existence of a valid and legal ground for termination. Without a recognized just or authorized cause, the dismissal cannot stand.
Procedural Due Process: Even if a valid cause exists, the employer must follow the correct procedure, known as the "twin-notice rule," when terminating employment. This includes:
- First Notice: A written notice specifying the act or omission that serves as the basis for termination, giving the employee a reasonable opportunity to explain and defend themselves.
- Opportunity to be Heard: The employee must be allowed to respond, either in writing or through a hearing, to address the charges raised. This ensures that the employee’s side is fully ventilated before a final decision is made.
- Second Notice: After due consideration of the employee’s explanation, a subsequent written notice informing the employee of the decision to terminate, should the employer find them culpable.

5. The Principle of Proportionality and Reasonableness

Employers must ensure that the penalty of dismissal is commensurate to the gravity of the offense. Even if a just cause exists, if dismissal is too harsh under the circumstances, it may be set aside as an illegal dismissal or result in reinstatement without full backwages. Philippine jurisprudence is replete with cases emphasizing this principle of fairness and proportionality.

6. Effects of Non-Compliance with Due Process

Failure to comply with substantive due process (i.e., dismissing without just or authorized cause) results in a finding of illegal dismissal. The standard remedies include:
- Reinstatement: The illegally dismissed employee is entitled to be restored to their former position without loss of seniority rights.
- Full Backwages: The employee is generally entitled to payment of salaries, allowances, and other benefits they would have received from the time of dismissal until actual reinstatement.
Failure to comply with procedural due process (even if substantive due process is met) may result in the payment of nominal damages to the employee, as set by jurisprudence, to vindicate the violation of their right to due process.

7. Authorized Causes: Additional Requirements

While authorized causes (e.g., redundancy, installation of labor-saving devices, retrenchment to prevent losses, closure or cessation of operations, disease preventing the employee’s continued employment) are generally business-related and do not stem from an employee’s fault, employers must still follow legal requirements such as:
- Written notices to both the employee and the DOLE at least 30 days prior to the intended date of termination.
- Payment of separation pay, where required by law, calculated based on the nature of the authorized cause.
The existence of an authorized cause must be supported by substantial evidence (for instance, proof of actual or imminent financial losses for retrenchment).

8. Prohibited Grounds for Termination

Discrimination and arbitrary dismissal without lawful cause are strictly prohibited. Termination based on race, gender, political or religious beliefs, union membership, or the exercise of protected constitutional rights is illegal. Philippine law strongly guards employees from retaliatory or prejudicial dismissals.

9. Fixed-Term Employment and Project Employment

In cases of fixed-term or project employment, expiration of the term or completion of the project is generally recognized as a valid ground for termination, as long as such arrangements were not used to circumvent security of tenure laws.
The employer need not show just or authorized cause for separation upon the completion of the term or project, provided the engagement was validly fixed and not a mere ploy to deny regularization.

10. Probationary Employment

During the probationary period, the employer may terminate an employee who fails to meet the reasonable standards made known to them at the time of engagement. However, even in probationary dismissals, due process dictates that the employee be informed of the grounds for termination and given a chance to explain.
If the probationary employee was not properly apprised of the performance standards or was dismissed for reasons unrelated to their performance, the termination may be held illegal, entitling them to the same remedies as a regular employee.

11. Managerial Employees

Managerial employees may be terminated for loss of trust and confidence more readily than rank-and-file employees, provided such trust is essential to the position and the loss thereof is willfully caused or induced by the employee’s own acts.
Nonetheless, the principles of just cause and due process remain applicable. Mere allegations of loss of trust and confidence must be supported by clear and convincing evidence.

12. Record-Keeping and Documentation

Employers are advised to thoroughly document any infractions, disciplinary proceedings, and steps taken to comply with due process. Well-kept records strengthen the employer’s case before labor tribunals and the courts should the termination be challenged.
Proper documentation includes the notices issued, the employee’s response, minutes of hearings or investigations, and any supporting evidence of misconduct, business necessity, or other termination grounds.

13. Remedies in Case of Illegal Dismissal

If the National Labor Relations Commission (NLRC), the Labor Arbiter, or the courts find that the dismissal was illegal, the primary remedies are reinstatement without loss of seniority rights and full backwages from the time of dismissal up to the date of actual reinstatement or finality of the decision.
If reinstatement is no longer viable due to strained relations or business closure, the employee may be awarded separation pay in lieu of reinstatement in addition to backwages.

14. Evolving Jurisprudence and Department Issuances

Philippine labor law continues to evolve through Supreme Court rulings and DOLE’s issuance of Department Orders and Labor Advisories. Employers must remain updated, as nuances in procedural requirements, interpretations of just causes, and formulae for computing backwages and damages are refined over time.
Recent jurisprudence emphasizes the strict adherence to procedural due process, the protection against constructive dismissal, and the significance of providing substantial evidence to justify terminations.

In Summary:
"Generally," termination by an employer under Philippine labor law is never a mere prerogative exercised at will. It is circumscribed by constitutional, statutory, and regulatory protections ensuring that employees enjoy their right to security of tenure. Employers must have a lawful cause and follow mandatory procedural steps. Any failure on either substantive or procedural aspects can result in serious legal and financial consequences for the employer. At the core of these rules is the balancing act between an employer’s legitimate business interests and the employee’s fundamental rights to continuity of employment and protection against unjust and arbitrary separation.