The third season of Shameless, an American comedy-drama television series based on the British series of the same name by Paul Abbott, premiered on January 13, 2013, at Sunday 9:00 p.m. EST on the Showtime television network. Executive producers are John Wells, Paul Abbott and Andrew Stearn, with producer Michael Hissrich. The season concluded after 12 episodes on April 7, 2013. The show's season premiere brought in 2.00 million viewers, becoming the show's highest-rated episode ever to-date. The episode airing February 17, "The Sins of My Caretaker", received 1.31 million total viewers, its lowest-rated episode of the season. The season finale scored 1.82 million viewers.

Fiona struggles to adapt to life with Jimmy, as he officially moves in with the Gallaghers. Jimmy, however, has more pressing concerns when Estefania's drug lord father, Nando, returns to the United States. Nando kills Marco and forces Jimmy to dismember the body; he also tells Jimmy that he wants him to stay married to Estefania, so Estefania can become an American citizen. Out of fear for his life, Jimmy agrees, but he keeps it a secret from Fiona.

Frank calls Child Protective Services on his own family after being kicked out of his own house once again. When a CPS worker comes for a visitation at a particularly hectic time, the underage kids are forced into separate foster homes, many being less-than-adequate. Though Veronica and Kevin attempt to foster the kids, Fiona ultimately gets Frank to clean up for their foster worker. When Fiona finds out Frank is the one who called CPS, Fiona fights for custody of the children against Frank, and is declared their legal guardian. This is bad news for Jimmy, who had plans to go to medical school in Michigan. Though Fiona, albeit shocked, is initially supportive, she is enraged to find out Jimmy had applied for a studio apartment only. After she and Jimmy get into a nasty argument over their relationship, Fiona breaks up with him.

Ian continues his relationship with Mickey, and their relationship continues to grow in the first half of the season. After the Gallagher children are put into foster homes, Mickey invites Ian to stay with him while his father, Terry, is out of town. However, Terry comes home early and unexpectedly walks in on them having sex. Terry—who is abusive and homophobic—beats the two boys at gunpoint and forces Mickey to have sex with a Russian prostitute, Svetlana; Mickey is thereby damaged and refuses to communicate with Ian. To Ian's dismay, Mickey marries Svetlana, who has become pregnant with his child. Meanwhile, Mandy and Lip are together, though Lip begins feeling smothered by Mandy when she becomes more involved in his life. Worried that Lip will throw away his future, Mandy secretly applies Lip for several colleges, and a successful interview gives Lip a chance at MIT. Lip thanks Mandy for her help. Kevin and Veronica continue their quest to have a baby, but there is little chance of Veronica getting pregnant; Veronica asks her mother to be their surrogate.

Family troubles are not limited to the Gallaghers: Sheila is struggling to deal with parental life, and her problems are further compounded when Jody relapses in his sex addiction. Sheila desperately lets Frank offer his support with Hymie, which leaves him with a temporary home. When Timmy Wong's family want Hymie to live with them, Sheila reluctantly obliges, realizing that her home is an unsuitable environment to raise a baby. Later the next day, Karen returns home. Sheila is overjoyed by Karen's return, but after speaking with Timmy Wong's mother, Sheila discovers that Karen had previously called the Wong family to take Hymie away from her and Jody. Heartbroken by her daughter's actions, Sheila becomes depressed. Meanwhile, Karen briefly rekindles her sexual relationship with Lip, but Lip decides against pursuing their relationship in favor of Mandy. When Karen threatens Mandy through a phone call, Mandy vengefully runs over Karen with her car, which leaves Karen with possibly permanent deficiencies. Lip, upset over Karen's vegetative state, angrily breaks up with Mandy. To give Karen a better recovery, Jody and Sheila break up, and Jody leaves town with Karen and Hymie to Arizona.

The final episodes of the third season, while still comedic, begins to shift into a darker tone. Frank is diagnosed with liver failure and is advised to stop drinking or he will die. Fiona visits Frank in the hospital and tries to convince him to stop drinking for either himself or his kids, but he refuses. Depressed from Mickey's marriage, Ian enlists in the Army without the knowledge of his family, only revealing the news to a shocked Mickey. He leaves secretly the next morning, forging identification using Lip's ID. Meanwhile, Estefania is deported due to Jimmy's neglectfulness. Nando orders Jimmy to board a yacht to an unknown location, presumably for Jimmy to be murdered. Fiona begins a temp job at Worldwide Cup, and she sends a final voicemail to Jimmy's phone signalling that she is over him.

On February 1, 2012, Showtime announced the series would be renewed for a third season.^[13] The show's third season began shooting on June 27, 2012^[14] and premiered on Sunday, January 13, 2013.^[15]

Noel Fisher, Emma Greenwell and Zach McGowan were promoted to series regulars for their roles as Mickey Milkovich, Mandy Milkovich and Jody Silverman respectively. Laura Slade Wiggins was demoted to a recurring character for her role as Karen Jackson, after her character left in the second season's finale. Wiggins' character returns mid-way through the third season, in the episode "A Long Way From Home". Stephanie Fantauzzi, Vanessa Bell Calloway, and Tyler Jacob Moore return as recurring characters for their roles as Estefania, Carol Fisher, and Tony Markovich.

Review aggregator Rotten Tomatoes gives the third season a 92%, based on 13 reviews. The critics consensus reads, "Shameless divvies up a spoil of riches among its impoverished ensemble, further fleshing out all members of the Gallagher clan in surprising ways."^[16]