Short answer. Yes. Even though you become emancipated at 18, Republic Act 6809 provides that contracting marriage shall require parental consent until the age of twenty-one. So an 18-year-old is old enough to marry, but the law still requires the consent of the parents until you turn 21.
What the law says
Contracting marriage shall require parental consent until the age of twenty-one.
RA 6809, Section 3 — Effect Of Emancipation. Read the full provision →
Emancipation is not the same as full freedom to marry
Republic Act 6809 lowered the age of majority to 18 and, in amending the rule on emancipation, said that emancipation shall terminate parental authority over the person and property of the child, who becomes qualified and responsible for the acts of civil life. But the same amendment carved out marriage: contracting marriage shall require parental consent until the age of twenty-one. So although turning 18 ends your parents' authority over you generally, it does not end their say in this one decision. Between 18 and 21 you may lawfully marry, but the law treats the marriage as needing your parents' consent first.
Consent versus advice, and what age changes
Philippine law distinguishes between parental consent and parental advice. Consent is required for those below 21 who wish to marry; it is the parents' actual approval. Once you turn 21, that requirement falls away. There remains a separate, lighter requirement of parental advice for those between 21 and 25, but that is a different thing, and its absence delays rather than blocks the marriage. The line Republic Act 6809 draws at 21 is specifically about consent: below it, marrying without your parents' consent is not the free exercise of an adult right the way your other civil acts have become.
What happens if you marry at 18 without consent
Because the consent requirement is real, marrying between 18 and 21 without it has consequences. A marriage where a party is 18 or over but below 21 and lacks the required parental consent is not automatically void, but it is exposed to being annulled on the petition of the parent whose consent was needed, brought within the period the law allows. In other words, the law does not pretend the marriage never happened, but it gives the parents a window to have it undone. That vulnerability is the practical bite of the rule, and it lasts until the consent problem is cured by the passage of time.
What this means if you are planning to marry young
The takeaway for someone who is 18 and planning to marry is that adulthood in most respects does not carry over to this decision. You will be asked for proof of your parents' consent when you apply for the marriage licence, and a marriage entered without it stands on shakier ground until you both pass the age where consent is no longer needed. If a parent unreasonably withholds consent, the remedy is not to conceal it but to understand that the requirement is the parents' to insist on until 21. Where family circumstances are complicated, it is worth sorting the consent question before setting a date.