A cheerful movie import from Scotland, the new comedy "Gregory's Girl," opening today at the Outer Circle, reveals a distinctive talent for low-key, sweet-tempered social comedy.

But writer-director Bill Forsyth hasn't developed enough technique to put a sharp edge or fine polish on characterization, authentic social observation and comic dialogue. In a way the filmmaker's lack of coordination echoes the predicament of his protagonist, a likable gawk of a high school boy, played by Gordon John Sinclair. Sinclair's Gregory, suddenly all limbs as the result of a five-inch growth spurt, embodies the comedy of adolescent growing pains. Forsyth's direction seems to duplicate this awkward amiability.

The principal situation, Gregory's infatuation with an awesome, adorable creature named Dorothy (Dee Hepburn), who enters his life when she replaces him as the starting center forward on the school soccer team, never generates much dramatic momentum, or even friction. Gregory accepts her athletic superiority with doting equanimity. Dorothy makes the team offensively potent as well as uniquely attractive. Her dominance seems as natural and matter-of-fact as the position Gregory's pal Steve (William Greenlees, a wonderfully relaxed young performer) has evidently earned in the home ec department, where his cooking skills are so advanced that he's already a campus treasure, well on his way to a prosperous career.

Forsyth doesn't even pretend that anything of a drastic dramatic nature might happen as a result of Dorothy's impact on Gregory. His infatuation serves as a pretext for incidental, affectionate comic observation of changing and enduring adolescent behavior patterns, especially the awkward or devious maneuvers associated with preliminary mating games. However, Gregory is too awed by Dorothy and too gauchely self-conscious to work up the nerve to ask her out right away. By the time he makes a formal approach, the denouement is close at hand, and Forsyth springs a delightful plot twist in the waning moments, reminding us that the term "Gregory's girl" lends itself to a certain ambiguity. Given this setting and group of characters, the ambiguity seems inspired: The surprise rings true socially, psychologically and romantically. It also relieves you of the vague apprehension that Gregory may be blundering into an excruciating mismatch.

Forsyth also shows welcome signs of loosening up pictorially in the concluding sequences. There's a playful, gravity-defying shot and a stunning panoramic view of silhouetted figures at sunset. In a visually inventive, dynamic movie these compositions wouldn't necessarily stand out. Here they represent a sudden, stirring liberation from the boxed-in look that inhibits most of the footage. One takes these parting flourishes as an indication that Forsyth has just begun to feel confident behind the camera and may unwind decisively in his next movies.

Forsyth's good humor and good will make it easier to excuse the patchiness and intermittent coyness of "Gregory's Girl." In addition, the suburban Scottish setting provides a fresh source of cross-cultural observation and comparison. The location is Cumbernauld, a "new town" built outside Glasgow about 20 years ago. The domestic and scholastic environments inhabited by Gregory and his classmates have an exotically funny familiarity. They resemble the American suburbs in a number of respects, and it's conceivable that the resemblances are more than superficial. At the same time, the Scottish flavor adds a distinctive comic identity. One may recognize the architectural similarities between American and Scottish suburbia easily enough, but the cultural similarities are subject to eccentric, amusing national variations. For example, I doubt if any American pedagogue could duplicate the exquisite tone of dismissal achieved by Chic Murray as the headmaster of Gregory's school in one priceless episode. Interrupted by little intruders while practicing at the harmonium, Murray throws them a baleful glare and commands, "Off you go, you small boys."