Attorney Shawn Holley entered the plea during a brief hearing Tuesday in Los Angeles.
The actress is accused of lying to police, reckless driving and obstructing police from performing their duties.
Police suspect she was driving her sports car when it slammed into the truck while she was on her way to the set of "Liz and Dick" in early June. Lohan told police she wasn't behind the wheel.
Lohan was on probation for a 2011 necklace theft case at the time, and could face up to 245 days in jail if a judge determines she violated her probation.
(Copyright 2013 by The Associated Press. All Rights Reserved.)