Jerry's Cousin is a 1951 Tom and Jerry cartoon.
One day at Hogan's Alley, Jerry's cousin Muscles is showing the cats who's boss. After dispatching of his feline nemesis, Muscles retrieves his mail, which includes a letter from Jerry, begging for help in dealing with Tom.
An angry Muscles packs his bag and goes to Jerry's home. As he marches through the alleyway, the cats cower in fear; Butch is so scared of Muscles that he digs his own grave and buries himself.
At Tom and Jerry's house, the mouse is being mercilessly terrorized by Tom, who throws sticks of firecrackers into Jerry's mouse hole. Muscles arrives just as a stick of dynamite is thrown into the hole. Muscles goes out of the hole with the dynamite and forces Tom to endure the explosion in his mouth. This causes the cat's eyes, cheeks and eardrums to briefly pop out as smoke comes out of his ears. When Tom grabs Muscles, the mouse easily throws him off and sternly demands that, as long as Muscles is around, Tom lay off his little cousin Jerry "Listen Pussycat! Don't let me catch you picking on my little cousin while I'm around, you understand? Now beat it!" He then gives Tom a further taste of his strength by hurling him into a vase and spits on it, revealing that the cat has conformed into the vase's shape.
Tom tries weight training, but as he visits Muscles and gives Muscles a punch, Muscles blows his own hand into a very big one and punches Tom strongly. Tom then tries a divide and conquer strategy, and even attempts murder, but finds himself outwitted at every turn; Muscles is either too strong or too crafty for him. In desperation, Tom calls a group of feline thugs for hire to dispose of Muscles. Even though the thugs ambush Muscles, they are quickly immobilized and tossed from the house. Tom, thoroughly intimidated, begins to grovel at Muscles' feet. Before Muscles returns home, he gives Jerry an outfit which is identical to his, with him reminding him to whistle. Jerry gets himself dressed and toughen himself up to look more like Muscles. While Jerry steps out of his mousehole and whistles, Tom believes that Jerry is Muscles, rushes there to bow to him and kisses his feet, much to the mouse's delight.
- Cousin George made a cameo at the beginning when Muscles already knocked him out and hung him on a clothes' line, but in this short, he has black fur instead of blue.
- This is the fifth Tom and Jerry short to be nominated.
- This was the last short to have Tom and Jerry in their 1940's style.
- This is the first appearance of Muscles Mouse.
- The opening theme music for this cartoon was often reused in most cartoons of the Gene Deitch era, therefore, this version is associated with the Gene Deitch era. The opening theme music for His Mouse Friday and Slicked-up Pup were similar to this.
- This cartoon marks the first appearance of Muscles Mouse, and his only appearance in the "classic" era. A similar-looking character to Muscles named Freddie appears in the direct-to-video film Tom and Jerry: The Magic Ring (2001), except that in that film unlike Muscles who cares deeply of Jerry despite his tough-guy demeanor, Freddie, on the other hand, is a mean tough-guy bully whom is hostile towards Jerry and Nibbles. Muscles would later reappear as a recurring character in the reboot series The Tom and Jerry Show beginning with the episode Frown and Country from Season 3.
- The ending tune is "Hail to the Chief".
- Tom making a call with glasses on and the hired thugs became internet memes.
- When Tom grabs the bowling ball, it disappears only to reappear.
- Irven Spence is erroneously credited as Irvin Spence in the opening credits.