National Lampoon's Christmas Vacation is a 1989 comedy film directed by Jeremiah S. Chechik. It is the third installment in the National Lampoon's Vacation series of films.

It stars Chevy Chase as Clark Griswold, Beverly D'Angelo as Ellen Griswold, Johnny Galecki as Rusty Griswold and Juliette Lewis as Audrey Griswold. Randy Quaid and Miriam Flynn reprise their roles as, respectively, "Cousin Eddie" and "Cousin Catherine," from the first National Lampoon's Vacation film. Other supporting roles are played by Brian Doyle-Murray (who also appeared in the original Vacation film, although in a different and smaller role), E. G. Marshall, Doris Roberts, John Randolph, Diane Ladd, Nicholas Guest, Julia Louis-Dreyfus, William Hickey, Cody Burger, Ellen Hamilton Latzen and Sam McMurray. This was also Mae Questel's last role before her death.

It's Christmas time and the Griswolds are preparing for a family seasonal celebration, but things never run smoothly for Clark, his wife Ellen and their two kids. Clark's continual bad luck is worsened by his obnoxious family guests, but he manages to keep going knowing that his Christmas bonus is due soon. Written by Rob Hartill

Chicago resident Clark Wilhelm Griswold Jr has REALLY got the Christmas spirit this year, and his wife Ellen, son Rusty, and daughter Audrey have noticed it. Clark has invited Ellen's parents Arthur Smith and Francis Smith, his own parents Clark Wilhelm Griswold Sr and Nora Griswold, and his Aunt Bethany and Uncle Lewis to spend the holidays at the Griswold house in Chicago. Clark is obsessed with making everything go perfectly during the holiday season, but as soon as everyone arrives, things start going haywire, especially when the Griswolds receive some uninvited surprise guests from Kansas -- cousin Catherine, her sloppy husband Eddie, and two of their kids, Rocky and Ruby Sue. Clark decorates the outside of the house with 250 strands of lights with 100 bulbs on each strand for a total of 25,000 light bulbs, enough to make the power company turn on their auxiliary nuclear generator. Clark also annoys his snobby next door neighbors -- Todd Chester and his wife Margo. Even with his bumbling ways, Clark manages to keep things going as he waits for his Christmas bonus from work so he'll have enough money to have a swimming pool put in the back yard. But it turns out that Clark's boss, a scrooge whose name is Frank Shirley, does not intend to give out any Christmas bonuses this year, and this causes Clark to snap and act crazy. This situation gives Eddie the idea for the perfect Christmas gift for Clark after Clark offers to help Eddie treat Rocky and Ruby Sue to a good Christmas. Can Eddie help Clark and the family have a great Christmas? Written by Todd Baldridge

All Clark wanted to do is make Christmas nice with his family at their big home in Chicago. Instead of having an "Old Fashioned Family Christmas," Clark and the rest of the Griswold's got an evening of hell! Written by Jason Allentoff

It's Christmas time - Clark decided to invite all the family to have 'the most fun-filled old-fashioned family Christmas', which nobody shall ever forget. When the first relatives arrive, Clark soon flees on the roof to rig the lighting. The one thing the loving father wants to surprise the whole family with is the installation of a pool, which he already ordered. Unfortunately, the bonus check Clark expects any minute is overdue - and tempers rise, but not only because of the check. A big event is the arrival of uninvited cousin Eddie with his family in their mobile home, as well as a little sledding afternoon with a new lubricant from Clark's company, or his shifting relationship with the very hip and clean neighbours. Cousin Eddie chooses to top off all presents with his very own special creation, only intending to deliver a real reason to be jolly. Written by Julian Reischl