The first half of the Northern Virginia AAA Basketball season has not been kind to some teams, but at Yorktown and Oakton in particular, it has been especially harsh.

The Yorktown teams have a combined 1-20 record, the girls going winless through 11 games. It's much the same at Oakton, where the girls are 0-10 and the boys 1-11. In all cases, although at times it seems encouraging, the frustration continues to build.

The Oakton girls have been outscored by an average of 23 points per game, but Friday against W.T. Woodson, they led, 22-21, at halftime before losing, 54-37.

''We've usually been staying in games for three quarters,'' said Oakton's Sandy Reynolds, who is coaching at the varsity level for the first time after enduring a 1-20 season as junior varsity coach last year. ''Then we have a quarter where we score three or four points. That's what happened against Woodson. They outscored us, 20-4, in the third quarter.''

Oakton has just one senior, 5-foot-6 guard Kim Hardy. Reynolds thinks her team has a good future because she has made extensive use of 5-7 freshman Cathy Edmonds at point guard and 6-foot sophomore Samantha Stair at center.

Reynolds said one of the things that has made the season a little easier is beilng able to share her problems with Tom Casey, the boys coach. Casey is in his first year at Oakton after moving from Fort Hunt.

Still, nothing totally cushions the disappointment. ''I knew it was going to be tough -- I just didn't know how tough it was going to be,'' said Reynolds.

Jim Price, coach of the Yorktown boys, took teams to the Northern Region tournament in 1980 and 1981. This season, he has watched as, among other misfortunes, his team was shut out, 12-0, in the first quarter of a 74-47 loss to Langley.

''There have been only a couple of games where we've been blown out, and that's made it easier,'' said Price, who said he knows some of what his players go through off the court because of their record.

''I have to emphasize to the kids when we do things right, like play good defense, but it is a shame not everybody sees that from the stands. They just see the final score. If the final score is all we look at in life, a lot of people in this world would be in a lot of trouble.''

Losing on a regular basis is far from a problem at the Langley School, a private junior high in McLean.

Since Jim Gleason formed a girls basketball team five years ago, there was never a need for an after-game post-mortem until Friday, when Langley's 74-game winning streak was ended, 38-15, by visiltilng Georgetown Day.

''The team that beat us was good, and maybe a little more talented than us,'' said Gleason. ''But we were just atrocious. Everything went wrong. We missed easy shots and made just seven of 27 free throws.''

Gleason said not only were his girls in tears after the game, bukt so were Georgetown Day's.

''The last four or five minutes, when we realized we were going to lose, was a very emotional time,'' said Gleason. ''At the end, even their girls were crying because they knew we had never lost to anyone before.''