Mr. Blandings Builds His Dream House is a 1948 American comedy film directed by H. C. Potter, and starring Cary Grant, Myrna Loy and Melvyn Douglas.

[5] In the late 1940's, Jim Blandings, a successful account executive in the advertising business, lives with his wife Muriel and two daughters, Betsy and Joan, in a cramped New York apartment.

Planning to purchase and "fix up" an old home, they contact a real estate agent, who convinced them to buy "the old Hackett Place" in (fictional) Lansdale County, Connecticut—a leaning, dilapidated, nearly 200-year old farmhouse on some 35 acres where, they are told, General Gates stopped to water his horses during the Revolutionary War.

They buy the property for five times the going rate per acre for locals, provoking Jim's friend and lawyer Bill Cole to chastise him for following his heart rather than his head.

From the original purchase to the completion of the new home, a long litany of unforeseen troubles and setbacks—including digging a deep well only to find a spring just a few feet under the foundation—beset the hapless Blandings.

Bill observes that although he has been the voice of doom, pointing out all the ways they were being cheated, when he looks at what they have finally built, he realizes that some things "you do buy with your heart and not your head.

Jim, who is seen reading the book Mr. Blandings Builds His Dream House, invites the audience to “drop in and see us some time.” According to Time magazine, "Cary Grant, Myrna Loy and Melvyn Douglas have a highly experienced way with this sort of comedy, and director H. C. Potter is so much at home with it that he gets additional laughs out of the predatory rustics and even out of the avid gestures of a steam shovel.

Blandings may turn out to be too citified for small-town audiences, and incomprehensible abroad; but among those millions of Americans who have tried to feather a country nest with city greenbacks, it ought to hit the jackpot.

"[8] Bosley Crowther of The New York Times wrote that "as straight entertainment, this ambling and genial report on a young advertising man's disasters (and final triumph) in becoming a country squire is as much casual fun as can be looked for on our sparsely provided screen.

"[9] Variety called it "a mildly amusing comedy" with Grant "up to his usual performance standard," but found the script to be flawed when an "unnecessary jealousy twist is introduced, neither advancing the story nor adding laughs.

[27] Screen Directors Playhouse gave a second performance of its half-hour version on June 9, 1950, this time with Grant's wife Betsy Drake as Muriel.

[28] On January 21, 1951, Mr. and Mrs. Blandings, a weekly comedy radio series starring Cary Grant and Betsy Drake, premiered on NBC.

[37][38] In a promotion for the film, RKO built 73 replica houses around the US, such as Spokane in Washington;[39] Hartford, Bridgeport, Trumbull and Wethersfield in Connecticut;[40] Warwick in Rhode Island;[40] Worcester, Natick, Newton and Springfield in Massachusetts;[40] and Pittsburgh in Pennsylvania.