Is it permissible to kiss girls at feasts and on special occasions?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

If these girls are Mahram (non-marriageable) to you, it is permissible for you to kiss them on the hand, head, or forehead on the condition that there is no lust or desire involved or any potential fear of falling into sin, this condition is mostly met with one’s Mahram relatives by blood relationships more than it is with those from foster suckling relationships.

Imaam At-Tirmithi and Abu Daawood reported that the Prophet, sallallaahu ‘alayhi wa sallam, used to kiss Fatimah, his daughter and she used to kiss him.  Moreover, Imaam Ahmad ibn Hanbal was once asked about a Muslim man kissing one of his Mahram women and he said,“Yes, it is permissible when he arrives from travel on the condition that there is no fear of committing a sin.” Furthermore, he referred to the narration that was narrated by Khaalid ibn Al-Waleed that the Prophet, sallallaahu ‘alayhi wa sallam, came from a Ghazwah (i.e. a military campaign led by the Prophet) and he kissed Faatimah . Additionally, one should never kiss his Mahram women on the lips; instead he may kiss them on the head or the forehead.

On the other hand, if these girls are not Mahram to you, then it would be impermissible for you to kiss, touch, shake hands with, or even look at them. Unfortunately, many Muslims have been rather lenient and lax in this regard; therefore, they have incurred numerous woes, troubles and violations of honor (i.e. indecent assaults). All this is borne out in this life, yet, the punishment that would be afflicted upon them in the Hereafter are much more severe unless Allaah The Exalted bestows His mercy upon them.  

Allaah Knows best.