Greetings Angela, welcome to the Disney Parks Moms Panel.
Halloween is such a fun time at the Disneyland Resort. Besides enjoying the Haunted Mansion Holiday and seeing Mickey and Friends dress-up in costumes, my family and I love Mickey's Halloween Party, which is held on select nights in September and October. Dates for Mickey's Halloween Party are usually announced in the summer. According to the Disney Parks Blog, 2015 Mickey's Halloween Party dates were announced in mid-July.
I highly recommend checking the
Disneyland Resort Website and
Disney Parks Blog when summer rolls around. There are limited tickets for Mickey's Halloween Party and these exciting events do sell out quickly. Guests can purchase these special event tickets on the Disneyland Resort Website.
(Please note: Valid park admission is required in order to enjoy Mickey's Halloween Party, a separate, ticketed event.)
I hope this information is helpful in planning your trip to the Happiest Place on Earth. Please come back to visit me if you have further questions!
Have a magical day,
Kiki