Goofs

While at the beach house party Ryan picks up a cup and Marissa takes it and drinks from it before he has had a chance to put anything in it.

When Ryan is lighting Marissa's cigarette with his own it first shows a little burned off his cigarette, but in the next angle it shows the cigarette burned down to the filter and when Ryan goes to take a smoke his cigarette is back to almost full.

When Marissa is passed out and her friends leave her on the sidewalk, her body changes places between shots. At times her head is on a line of grass, but at other times the grass is under the small of her back while her head is on the concrete.

When pulling into the driveway after Sandy picks Ryan up from Chino, the car's trunk, which has a bike in it, is open when they drive away from Chino, closed when they pull into the driveway, and the open again when they get out.

Unless all of the characters were held back a year in school, their ages do not match their grade. In the first season, Marissa says she is 16 and her mother says Marissa was born in 1988, even though she is an incoming Sophomore, and should only be 15. This is also evident in the fact that Luke, Summer, and Marissa can all drive cars with no legal drivers.