Marcia Mae Jones received fan mail from disabled children all over the world after playing Klara in this movie.
For the scene in which Heidi is butted by a goat and falls over, Shirley Temple was butted for the first few takes. Although she later said that being butted was not painful, her mother Gertrude Temple became concerned for her safety and insisted that a stunt double be used.
Shirley Temple developed throat problems after she accidentally swallowed fake snow during a winter scene, and the crew had to shoot around her for two days.
As she had worried about Jane Withers in Bright Eyes (1934) three years before, Shirley Temple's mother, Gertrude Temple, worried that Marcia Mae Jones would steal the spotlight from her daughter in this movie. However, Shirley and Marcia Mae worked well with each other and appeared together again in The Little Princess (1939).
The movie was filmed during the summer, and Jean Hersholt's heavy costume once caused him to collapse from heat exhaustion.