We examined changes in loneliness over time. Study 1 was a cross-temporal meta-analysis of 48 samples of American college students who completed the Revised UCLA Loneliness Scale (total N = 13,041). In Study 1, loneliness declined from 1978 to 2009 (d = −0.26). Study 2 used a representative sample of high school students from the Monitoring the Future project (total N = 385,153). In Study 2, loneliness declined from 1991 to 2012. Declines were similar among White students (d = −0.14), Black students (d = −0.17), male students (d = −0.11), and female students (d = −0.11). Different loneliness factors showed diverging trends. Subjective isolation declined (d = −0.20), whereas social network isolation increased (d = 0.06). We discuss the declines in loneliness within the context of other cultural changes, including changes to group membership and personality.