The New York Times opens with this:
It is seldom that there comes a motion picture which can be wholly and enthusiastically endorsed not only as superlative entertainment but as food for quiet and humanizing thought. Yet such a one opened at the Astor last evening. It is "The Best Years of Our Lives."Variety calls it "one of the best pictures of our lives." Slant Magazine gives it 3.5 out of 4 stars and says, "if The Best Years of Our Lives emerges as a more contemporary-seeing film than almost anything else to which its ingredients could compare, it’s because of how it wrestles with the burden of patriotism."
Roger Ebert has it on his list of Great Movies and says,
Seen more than six decades later, it feels surprisingly modern: lean, direct, honest about issues that Hollywood then studiously avoided. After the war years of patriotism and heroism in the movies, this was a sobering look at the problems veterans faced when they returned home.Rotten Tomatoes has a critics score of 96%. 1001 Flicks has a review.