Spokesmen for several national antidrug organizations and D.C. Delegate Walter Fauntroy announced yesterday that they will hold a "celebration of the family" on July 4 at Lafayette Square as part of a national campaign to eliminate teen-age drug abuse and strengthen family values.

In hosting the celebration, the organizers of the celebration have thwarted the efforts of a pro-marijuana group, the Youth International Party, commonly called Yippies, to hold their annual July 4 marijuana smoke-in at Lafayette Square. The antidrug groups applied for a permit to use the square one day before the Yippies applied for one. A spokeswoman for the U.S. Park Service said that permits to use the square are approved on a first-come, first-served basis.

The celebration, a program of speeches and musical entertainment, is being sponsored by the National Federation of Parents for Drug-Free Youth, the D.C. Congress of Parents and Teachers, the local chapters of Toughlove and Straight, Inc.--two staunch antidrug groups--and several dozen other family and antidrug organizations. Fauntroy said that the groups represent "a serious but informal coalition to reinforce the support for a healthy environment for our children."

The annual smoke-in had become something of a tradition for the Yippies, a frail coalition of survivors of the turbulent '60s. Last year some 500 people gathered in Lafayette Square to protest what they called repressive enforcement of the nation's antimarijuana laws. They burned hundreds of blank Selective Service registration forms and lit marijuana cigarettes.

But this year, said Judy Reidinger, of the National Federation of Parents for Drug-Free Youth, "we decided it was our turn to speak up for what we think is important. What better time and place is there to celebrate one of the keys to keeping our country healthy and strong and free?"

Fauntroy said that he and other members of Congress are sponsoring a House joint resolution to designate July 4 this year "Family Celebration Day."

Asked about alternate plans for the July 4 Smoke-In, Dana Beal, a Yippie member, said yesterday, "We will be there at Lafayette Square . We would like to make this the most memorable and interesting smoke-in since 1970." He would not elaborate.