模板:Infobox television 三人行 是一部 美國情境喜劇 ，從 1977 至1984於ABC播放。 本劇是英國情境喜劇Man About the House的重拍 Jack Tripper 自從一場派對結束後被發現睡在Chrissy Snow 和 Janet Wood合租的公寓裡的浴室之後，就搬進來合住了。為了被允許可以住在一起, 傑克讓兩位房東， 史丹利 和 海倫 Roper (and subsequently, Ralph Furley)，相信他是個男同性戀.
三人行 spawned two spinoffs, The Ropers, revolving around Jack's former landlords, and Three's a Crowd, the further adventures of Jack as he settles down. Neither was as popular and both were swiftly cancelled. (Both were based on George and Mildred and Robin's Nest, successful spinoffs of Man About the House, as they actually produced more episodes than the original).
Suzanne Somers 在本劇中飾演金髮傻大姐Chrissy Snow後，成為受歡迎的明星。 She eventually caused friction on the set in 1980 when, after demands for a heavily increased salary were not met, she went on strike and was absent for several taping days. Eventually co-stars Joyce DeWitt and John Ritter refused to work with her because of this, but unwilling to fire the actor for fears her absence would cause ratings to decline the producers of the series retained Somers, who was still under contract, to appear in just the one-minute tag scene of each episode. According to scripts she had returned to her home town, and in the tag scene she would be seen on the telephone to one of the series regulars who would recount that episode's adventures to her. Somers' scenes were taped on separate days from the show's regular taping; she did not appear on set with any of the show's other actors. 如此的安排維持一季之久，但在她的合約到期而不再續約後，就在此劇中消失了。
在本連續劇即將告尾聲之際，廣告裡暗示Jack Tripper和Janet Wood 將會結婚，然而Janet 事實上卻是和另一位男子結婚，Jack後來開了一家餐廳，和他的女友進駐。
本連續劇是設定在 Santa Monica, California，場景通常集中在三個地點，分別為三人同住的公寓、房東的公寓和當地名為"The Regal Beagle."的餐廳。在後幾季當中，因為傑克的小餐廳被設定為主要場景，Regal Beagle was seen 也就沒這麼常出現了
- John Ritter as Jack Tripper (full run), 一個笨拙的廚藝學生，同時也是個為了能和兩位女室友同住而假裝是男同性戀的單身漢。之後他經營他自己的餐廳名為 "Jack's Bistro."
- Joyce DeWitt as Janet Wood (full run), the down-to-earth brunette who worked in a "flower shop."
- Suzanne Somers as Chrissy Snow (1977-1981), 工作為打字員的金髮傻大姐
- Jenilee Harrison as Cindy Snow (1980-1982), Chrissy's equally ditzy cousin and her replacement in the apartment.
- Priscilla Barnes as Teri Alden (1981-1984), Cindy's replacement, a non-ditzy, intelligent blonde nurse who seemed to be the show's answer to complaints about their portrayal of blondes.
- Norman Fell (1977-1979) as Stanley Roper, the hard-nosed landlord who seemed obsessed with Jack's sexuality.
- Audra Lindley (1977-1979) as Helen Roper, the landlord's wife, who was always friendly to the "kids" in the apartment and frustrated that her husband never wanted to have sex.
- Don Knotts as Ralph Furley (1979-1984), Mr. Roper's replacement, the goofy, flamboyantly dressed landlord who was running the place for his brother Bart.
- Richard Kline as Larry Dallas (1978-1984), the womanizing neighbor who was a used car salesman.
- Ann Wedgeworth as Lana Shields (1979-1980), the neighbor who pursued Jack, and in turn was pursued by Furley.