Question: Is it wrong to celebrate Halloween?
Answer: It appears that various pagan, superstitious, and demonic activities were originally centered around October 31st. Perhaps to offset or counterbalance this atmosphere, the Catholic Church instituted both Halloween ("All Hallowed Eve") and the day that follows, "All Saints Day", as religious holy days. One encyclopedia defines Halloween as "in medieval times All Hallows Eve, a holy or hallowed evening observed on October 31, the eve of All Saints' Day". Both holy days are foreign to the scriptures.
Blending of Catholic and pagan influences. Tracing the origin of Halloween back to its pagan roots, it was originally believed that the souls of the dead were supposed to revisit their homes on this day and sinister importance was assigned to October 31. Pagan association involved ghosts, witches, black cats, and demons of all kinds. On October 31 it was believed that supernatural powers controlled nature. The foregoing pagan observance influenced the religious festival of All Hallow's Eve, which was also celebrated on October 31. Hence, Halloween is the result of the blending of the pagan and the religious. However, many in America today do not attach any religious meaning to Halloween. For reference, see the citation on this subject from the ENCYCLOP∆DIA BRITANNICA below.
Care needed. Considering the close association of the modern observance of Halloween with demons, witchcraft, black magic, sorcery, evil spirits, and such like, a Christian should be very careful about "celebrating" such a holiday. And for sure, churches have no authority for observing Halloween. Note the contrast between such and the attitudes of Acts 19:19. As a side comment, a similar lack of Biblical authority applies to the religious observance of other "holy days", like Easter, Christmas, and such.
From the ENCYCLOP∆DIA BRITANNICA for "Halloween"
Halloween also called ALL HALLOWS' EVE or ALL HALLOWS' EVENING a holy or hallowed evening observed on October 31, the eve of All Saints' Day. In modern times, it is the occasion for pranks and for children requesting treats or threatening tricks. In ancient Britain and Ireland, the Celtic festival of Samhain eve was observed on October 31, at the end of summer. This date was also the eve of the new year in both Celtic and Anglo-Saxon times and was the occasion for one of the ancient fire festivals when huge bonfires were set on hilltops to frighten away evil spirits. The date was connected with the return of herds from pasture, and laws and land tenures were renewed. The souls of the dead were supposed to revisit their homes on this day, and the autumnal festival acquired sinister significance, with ghosts, witches, hobgoblins, black cats, fairies, and demons of all kinds said to be roaming about. It was the time to placate the supernatural powers controlling the processes of nature. In addition, Halloween was thought to be the most favourable time for divinations concerning marriage, luck, health, and death. It was the only day on which the help of the devil was invoked for such purposes. The pagan observances influenced the Christian festival of All Hallows' Eve, celebrated on the same date. Gradually, Halloween became a secular observance, and many customs and practices developed. In Scotland young people assembled for games to ascertain which of them would marry during the year and in what order the marriages would occur. Many Halloween customs have become games played by children. Immigrants to the U.S., particularly the Irish, introduced secular Halloween customs that became popular in the late 19th century. Mischief-making on this occasion by boys and young men included overturning sheds and outhouses and breaking windows, and damage to property was sometimes severe. In later years, the occasion has come to be observed mainly by small children, who go from house to house, often in costume, demanding "trick or treat" (the treat, often candy, is generally given and the trick rarely played). Since 1965, Unicef, an agency of the United Nations, has attempted to incorporate into the Halloween observance the collection of money for the United Nations Children's Fund. A common symbol of Halloween is the jack-o'-lantern (the name possibly was derived from that for a night watchman). It is a hollowed-out pumpkin carved in the appearance of a demonic face and with a lighted candle fixed inside. In Scotland a turnip was used, but the native pumpkin was substituted in the United States.