When is the best time (least crowded) to go to Disney World?
We get this question over and over, again. When's the best time to go to Disney? When are the crowds the lowest?
The short answer is when it's most difficult for people to go! 
Seriously, the slowest time's at Disney World are when it's likely to be most difficult for the majority of travelers to leave home and come to Disney World. Obviously, this does not include the summer months!
The least crowded times for Disney World include:
- Right after Labor Day until Thanksgiving -- this is right after you've put your kids back in school and there are no long holidays for you to take a long vacation. Although this has typically been a good time, Disney has recently been offering lots of promotions during this time-frame to boost attendance (such as the recent free dining extension). I've found in recent years that this time of year is still quite busy.
- 2nd week of January through the 1st week of February -- again, right after you've put your kids back in school after a long holiday break. For me, this is the best time of the year to go to Disney. For us Floridians, it's a bit cold, but I just bundle up and enjoy not sweating off 100 pounds in the mid-summer Florida heat. This has become one of the few, truly slow times at Disney World
- Lastly, the weeks between Thanksgiving and Christmas are typically pretty slow. People are just off one holiday, working hard up to the next one. With only a few weeks in-between the two holidays and people working holidays to have the weeks after or before off, this one tends to get squeezed to a smaller time-frame every year. It's still a good time to go, if you're able, though.
These are the absolute best times to go to Disney World, if you're looking for low attendance, short lines, and maximum opportunity for show and dinner reservations. Some other options for slow to average attendance numbers include the 1st week of January (after New Year's Day) and the 2nd week of February through President's Week.
Disney World continues to offer many promotions during slow and average attendance periods to maximize park and resort bookings, so the "slow" times of the year have tended towards the non-existent side of the attendance spectrum. The real key to a fantastic Disney World experience is to plan your vacation beforehand and follow that plan (Shameless plug alert: and of course, get the Insider's Guide to Disney to REALLY maximize your vacation time and efforts).