It's not technically a lesbian movie, since the girls never explicitly consummate their relationship, but "The Secret of Bear Mountain". It's a Disney film that was apparently supposed to be a girl's version of Tom Sawyer, instead it watches as a rather sensitive portrayal of two teenage girls falling in love... with voiceover narration implying that the women are still together in adulthood.
They throw in a quick convo about "seeing guys naked", probably to try to offset the Les Yay, but it's still extremely strong.