Owen Lars was the son of moisture farmer Cliegg Lars and the stepbrother of Anakin Skywalker. He married Beru Whitesun, and after his father's death, he inherited his job as a moisture farmer. In 19 BBY, Beru convinced Owen to adopt Anakin's son, Luke Skywalker, as Anakin had turned to the dark side and became the infamous Darth Vader.
Owen and Beru raised their nephew as well as they could, and Owen instilled into Luke the values of his own childhood. Fearful of Luke's potential, and distrustful of the outside galaxy, Owen attempted to keep Luke isolated and ignorant of his true parentage.
Owen Lars is the son of Cliegg Lars, husband to Shmi Skywalker-Lars, who is mother to Anakin Skywalker, aka Darth Vader.
Anakin has twins with Queen Padme Amidala, who dies in childbirth. After Padme's death, Obi-wan Kanobi brings Shmi's grandson, Luke, to Owen and his wife Beru to raise. Owen & Beru raised Luke for 22 years. When Luke went into the Jungland wastes with C-3PO to recover a missing R2-D2 - acquired by Owen to work on the moisture farm - Imperial stormtroopers showed up at the Lars homestead, hunting for the robots. When Owen & Beru are unable to turn over the droids or provide the troopers with their location, the Imperials savagely murder Owen & Beru and burn the moisture farm to ashes. Luke, realizing the danger Owen & Beru are in, returns to the homestead, only to find the Imperials gone, the moisture farm a smoking ruin, and worse - outside the entrance, he finds the smoldering, skeletal remains of Owen & Beru.
In the original film, "A New Hope" Luke Skywalker refers to the character as "Uncle Owen."