"A New Day" is the 11th episode of the fourth season of the HBO original series The Wire. Written by Ed Burns from a story by David Simon & Ed Burns, and directed by Brad Anderson, it originally aired on November 26, 2006.

The title is spoken by Detective Greggs in reference to the new mayor's plans for the city. It may also refer to the New Day Co-Op where Proposition Joe conducts business.

McNulty uses this phrase to explain to Bodie his dislike of Officer Walker and his feeling that Walker got what he deserved. This can also refer to the consequences of Proposition Joe's actions in bringing Marlo into the New Day Co-Op (i.e. Omar and company making plans to rob the next shipment).

Although credited Chad L. Coleman, Glynn Turman, and Corey Parker Robinson do not appear in this episode.

Namond Brice buys dinner for his friends Michael Lee, Randy Wagstaff and Duquan "Dukie" Weems. They sit on a stoop with Donut and discuss the recent murder of Little Kevin. Randy is dismayed to learn of Kevin’s death. Leaving the laundromat, Officer Walker walks by and tells the boys to move on, accusing them of being up to no good. The boys plan revenge on Walker for his brutal assault on Donut. Michael says he knows of a bar that is well known as a police hangout that Walker frequents and vows to handle the problem.

Later, Namond, Randy and Dukie express doubts about Michael's plans for Walker, but they proceed regardless. Michael does not hesitate. As Walker leaves the bar, Duquan scratches Walker’s car, luring Walker to chase him into an alley. In the alley, Michael confronts Walker with a gun, ordering Walker to turn around and kneel. He takes the ring that Walker is wearing (which Walker had taken from Omar, who in turn had stolen it from Marlo after Old Face Andre surrendered it), and then gives a signal to Namond, who then douses Walker with yellow paint.

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