Over the years and throughout her career, Betty Lynn appeared in films such as "Cheaper by the Dozen" and televisions shows like "Family Affair," "Walt Disney's Wonderful World of Color," "My Three Sons," "Matlock," "The Smothers Brothers Show," "Little House on the Prairie," and "Barnaby Jones" (via Celebrity Net Worth).
Of course, her most notable role was that of Thelma Lou on "The Andy Griffith Show" from 1961 to 1966, and she received a TV Land Legend Award for this in 2004. "I had seen the Griffith show twice before I went to read for the part," she said. "I remember that I laughed out loud — it was so funny." Her character and Don Knotts' character, Barney Fife, even went on to tie the knot in the made-for-TV movie "Return to Mayberry" in 1986 (via Facebook).
At the time of her death, Lynn's net worth was $3 million, as stated on Celebrity Net Worth.
