It depends on what you move it to, which is why you need to be very careful.
To avoid a transfer being taxable you want to do a rollover to a traditional IRA which is also a tax-deferred account. Typically, the plan will send you a check made out to your broker followed by "FBO (your name)". FBO stands for "For the Benefit Of". You then deposit the check into your traditional IRA account with your broker. At tax time, your plan will send you a 1099-R for the withdrawal from the plan but with coding that it was a rollover. So it will be reported on your tax return but not included in income since it is a rollover.