Det. Martin "Marty" Crane was a character on the American television show Frasier. He was played by Lancashire-born actor John Mahoney. Martin is the father of Frasier and Niles Crane.

Unlike his sons, Martin Crane is very down-to-earth and unpretentious. His tastes are generally simpler than those of his sons and reflect popular culture to a greater degree - he prefers drinking beer (specifically Ballentine) to wine or spirits, for example, and prefers watching action movies and professional sports to the opera and theatre preferred by Frasier and Niles. He is a big fan of the Mariners, the Sonics, and the Seahawks, professional sports teams based in Seattle. In the earlier seasons especially, most of the comedy and drama of the series stems from the culture clashes between the refined sons and the blue-collar father (the sons frequently considering themselves superior in both taste and intellectual matters to their father, Niles once admitted that he often doesn't listen to Martin's advice because he "doesn't have any credentials"), and the struggles between Frasier and Martin in sharing an apartment. Among one of the disputes between Frasier and Martin is a decades old, well-worn recliner that Martin owns; Frasier is appalled by its appearance in his living room. Initially Frasier figures the perfect present for his father is to purchase him an expensive leather recliner that replaces Martin's old one. This greatly upsets Martin when he explains the sentimental value of the chair to Frasier, who feels extreme guilt and proceeds to get the recliner back for his father and returns the new one. Later, Frasier accidentally destroys the chair, and to make amends has a replica built at great expense (remarking that, ironically, it was now the most expensive piece of furniture in his apartment).

As a result, Martin has a complex and frequently difficult relationship with both his sons, both of whom take after their mother, and have little interest in the traditionally masculine pursuits that interest Martin, such as sports and outdoor activities, just as Martin himself finds little of interest in their pursuits, such as cooking, collecting antiques and opera. Martin also places little stock in (and is frequently and loudly dismissive of) established psychiatry, something which - as both of his sons are passionate psychiatrists - also undoubtedly contributed to the rift between them. On a few occasions, however, he actually exhibits genuine psychological know-how and intellect, surprising Frasier and Niles (although Martin usually waves off these situations and thinks nothing of it; he can, at times, attribute this to his listening to Frasier's radio show). Martin also frequently clashed with and was vocally dismissive of both of his sons' romantic interests (in particular their wives, Maris, and Lilith), which also added to the bad feeling between the men. Martin does not hesitate in telling his sons of their attitudes, on one occasion telling them that their mother never displayed snobbery.

A dramatic irony frequently shown in the series is that while Frasier and Niles may possess more intellectual knowledge and refinement than Martin, it is in fact Martin who is a wiser and more pragmatic individual. Certainly, Martin possesses greater reserves of common sense and experience than his two sons, and while his sons may be trained in psychiatry, it is frequently Martin's advice in any scenario that is more sound. Much to Frasier's consternation, Martin displays a rather shrewd native intelligence in playing chess, despite his lack of formal education, and he bests Frasier in all but one game (that Martin likely threw just to satisfy his son). He is usually quick to foresee the catastrophes and crises that Frasier and Niles' various plans and actions will result in, and is capable of advising the best way to avoid this - however, their senses of superiority, stubbornness and neuroses frequently ensure that Frasier and Niles will disregard his advice and blunder into chaos anyway. This can lead to Martin at times taking an almost gleeful delight in the misfortunes and downfalls of his sons, and he is often quick to point out that he told them so. However, Martin is prone to letting his stubbornness get in the way of happiness, that Frasier often helps him solve, such as forcing Martin to acknowledge his feelings for one romantic partner, Sherry Dempsey.

Martin is a gruff and taciturn man who finds it difficult to express himself emotionally - in particular to his family and loved ones, with whom he can be quite withdrawn and remote. He often comes across as curmudgeonly and ungrateful to Frasier for taking care of him. In the episode "Breaking the Ice", for example, he finds it easier to say the words "I love you" to both his dog Eddie and his best friend Duke than he does to either of his sons. He is certainly less comfortable with emotional exchanges than either of his sons, who find it much easier to express themselves in such a fashion. His blunt, open manner can make him seem tactless and insensitive. He is quite stubborn, and is given to holding grudges. He has stated that he believes justice should be the same for everyone when he refused to help Niles take care of a legal problem for Maris; he has, nevertheless used his position as an ex-policeman for preferential treatment on occasion, such as when he flashed his badge to a border guard in order to alleviate his suspicions.

For all this, Martin is portrayed as an extremely likable and caring individual. He is usually enthusiastic about making new friends, and although he may find it difficult to express his feelings to his sons, he clearly loves them both, remaining proud of and devoted to them, and bitterly resenting any implication that this might not be the case. When Niles goes to a costume party as Martin and is asked to name his biggest disappointment in life, Niles' response (in character and slightly inebriated) turns this into a speech of his distaste for his and Frasier's pretentiousness, snobbery, and lack of athleticism before finally saying "if I had to choose my two biggest disappointments." Martin quickly cuts him off, angered at being portrayed "as a drunken jackass", and tells Niles that, while he and Frasier weren't what he was expecting, he's always been proud of them.