Chanukah Gelt is an age old minhag in Klal Yisroel. Where is the source for this custom and why is not prohibited because of חקות הגויים? Isn’t this what the non-Jews do by their holidays?
The Mishnah Berurah (סימן תר”ע ס”ק א’) quotes from the מגן אברהם the minhag to give tzedakah on Chanukah “נוהגין העניים לסבב בחנוכה על הפתחים” – On Chanukah the poor people have the custom to go around to the houses and collect money. The פרי מגדים explains the reason for this minhag, that the יוונים were מבטל the three pillars of תורה, עבודה, וגמילות חסדים. To remind us of this miracle one must learn Torah, daven and give hoda’ah which corresponds to avodah, and give tzedakah which corresponds to gemilus chasadim. The גירסא of the מגן אברהם which the Mishnah Berurah quotes is “נוהגין הנערים העניים לסבב בחנוכה על הפתחים” – The minhag is for the poor נערים to go around on Chanukah and collect.
Reb Dovid Cohen shlit”a suggests that the minhag of Chanukah Gelt started because of the minhag that the poor נערים would go around on Chanukah. In order not to embarrass the עניים, money was given out to everyone. The minhag of the Steipler zt”l was to give out Chanukah gelt only to those who were not married. According to the reason we just brought we can understand why. Since it was not to embarrass the נערים it could be that the מנהג was only to give to other נערים but not to those already married.
There is another reason for Chanukah Gelt. There is a minhag to give money to the Rabbeim. Reb Chaim Palagi zt”l in his sefer מועד לכל חי writes אשרי אדם שנותן למלמד של בניו כמו בפורים – praiseworthy is the one who gives money on Chanukah to his son’s melamdim, just as he does on Purim. Reb Yaakov Kamenetsky zt”l says that it is from here that the minhag of Chanukah gelt started. The parents would send the money to the Melamdim with their children. The parents started to also give money to the children themselves. According to this it is also reasonable to say the minhag is only to give Chanukah gelt to נערים.
A third reason is from the Ponovizher Rav zt”l. The Greeks prohibited learning Torah. When the yidden won and it was once again permissible to learn Torah, they would give money to the children to encourage them in their limud haTorah. To remember this, we give Chanukah Gelt to the children to encourage them in their learning. This reason might work for all ages! Many have the minhag to give Chanukah Gelt to married children as well.
According to all the reasons mentioned there is definitely no prohibition of חקות הגויים. This minhag did not at all come from the goyim. If anything the opposite is true and the goyim borrowed this custom from us.
The Kitzur Shulchan Aruch writes that it is especially important on Chanukah to support the לומדי תורה. The simple reason is as we say in the teffillah וזדים ביד עוסקי תורתיך the נס happened through the עוסקי תורתיך. To be מעורר this נס we support the לומדי תורה for without them the נס would never have happened.
Reb Yaakov Kamenetsky zt”l would give out Chanukah gelt on the fifth night of Chanukah. This was also the minhag of the Steipler zt’l. Reb Chaim Kanievsky shlit”a says the reason for this minhag is because the fifth night of Chanukah never falls out on Shabbos.
Prepared by R’ Avrohom Yehoshua Ziskind
 Sources:אור ישראל דיני ימי חנוכה,דרשו