Roger Chew Weightman (June 15, 1787 – February 2, 1876) was an American politician, civic leader, and printer. He was the eighth mayor of Washington, D.C. from 1824 to 1827.

Weightman was born in Alexandria, Virginia, in 1787, moving into the new capital in 1800 and taking an apprenticeship with a local printer. His father Richard Weightman was an emigrant from Whitehaven, England. Chew was his mother's maiden name.

Weightman bought the printing business in 1807, making him a congressional printer. He maintained a number of shops on Pennsylvania Avenue, about ten blocks from the White House, from about 1813 onward. He was a successful businessman, running a book store and owning several buildings, including ones used by the city for offices until City Hall was built.

Wieghtman served in the Army during the War of 1812 and fought at the Battle of Bladensburg. In August 1814, Weightman (by now a First Lieutenant in D.C.'s Light Horse Cavalry) was apprehended by the British troops descending on the White House during the Siege of Washington, a battle in the War of 1812, and was made to march with them to the Executive Mansion. Rear Admiral George Cockburn made Weightmann accompany the invaders into the mansion where the admiral teased him with mischievous relish. When Cockburn told him to select a memento of the visit, Weightman chose an item of value, only to be told by the admiral that everything of value would be destroyed and that he must instead select a worthless souvenir. Weightman choose a souvenir (albeit one of no monetary value) to remember the day the American capital was defeated.

After serving seven one-year terms as an alderman on Washington's city council, the council elected Weightman in 1824 to serve the remainder of the late mayor Samuel N. Smallwood's term. In 1826 he ran against former mayor Thomas Carbery; four years prior, Weightman had run against Carbery for mayor and lost by a narrow margin, but had then pressed the matter in court in a legal battle that lasted until the end of Carbery's term. In 1824, Weightman won more decisively by use of blustery promises and insults against his opponent. One handbill from the era reads,

NOTICE EXTRAORDINARY. R.C. Weightman, a man of known liberal principles; all those who vote for this gentleman at tomorrow's election, will have general permission to sleep on the Benches in the Market House, this intense warm weather. May the curse of Dr. Slop light on all those who vote for Tom Carberry.

While mayor, Weightman headed the 1825 committee for the inauguration of John Quincy Adams, then the following year chaired the national memorial committee for the president's deceased father and his successor Thomas Jefferson.

In 1827, Weightman became cashier of the Washington Bank, and resigned his position as mayor. He would run again, unsuccessfully, against Walter Lenox in 1850.