Short answer. The difference is the medium. Libel is defamation put in writing or in some other permanent form — print, broadcast, a posted message. Slander is oral defamation, spoken aloud. The imputation may be identical; the form it takes changes the article that applies and the penalty that follows.
What the law says
Oral defamation shall be punished by arresto mayor in its maximum period to prisión correccional in its minimum period if it is of a serious and insulting nature; otherwise the penalty shall be arresto menor or a fine not exceeding Twenty thousand pesos (₱20,000).
Revised Penal Code, Article 358 — Slander. Read the full provision →
Same imputation, different form
Both crimes punish a public and malicious imputation that tends to dishonour or discredit another. What separates them is permanence. Writing, printing, an engraving, a radio or television broadcast, a theatrical exhibition, a photograph — these produce libel, because the statement outlives the moment and can spread. Words shouted in a corridor or a market produce slander. There is a third form as well: an act that humiliates, with no words at all, is slander by deed. The elements a complainant must establish are otherwise the same across all three — a defamatory imputation, malice, publication to a third person, and an identifiable victim.
Slander comes in two grades
Article 358 of the Revised Penal Code splits oral defamation according to whether it is of a serious and insulting nature. Serious slander carries the heavier penalty; simple slander is punished by arresto menor or a fine. Nothing in the article defines seriousness, so it is judged from the whole setting: the words used, the social standing of the parties, the place and the occasion, whether there was provocation, and the personal relations between them. The very same insult can be grave between strangers in a workplace and slight between neighbours in the middle of a quarrel. Peso figures in this article are those set by Republic Act No. 10951 (2017), so older printings of the Code understate them.
Why the difference costs money
Libel carries a substantially heavier penalty than slander, and the gap widens online. Defamation committed through a computer system is punished under the Cybercrime Prevention Act, Republic Act No. 10175 (2012), which imposes a penalty one degree higher than ordinary libel. So the same sentence said aloud, printed in a newsletter, and posted on social media attracts three different exposures. Prescription differs too, and light offences prescribe very quickly, so a complaint over a spoken insult must be brought promptly or it can no longer be filed at all. Venue rules for libel are strict and unforgiving, which is a common reason cases are dismissed without ever reaching the merits.
What neither one reaches
An insult delivered to the target alone, with nobody else present, is not defamation — there is no publication. Abuse aimed at a group so large that no individual is identifiable usually fails as well. Privileged communications are protected: a statement made in the performance of a legal, moral or social duty, and a fair and true report of official proceedings made in good faith, do not carry the presumption of malice. Fair comment on a public officer's official conduct is likewise protected. A civil claim for damages runs alongside either charge. This is general legal information, not advice, and no result can be promised; you can book a consultation to have a specific statement assessed.