Daniel of St. Thomas Jenifer[a] (1723 – November 16, 1790) was an American politician and Founding Father who was one of the signers of the Constitution of the United States.

He was active for many years in the Province of Maryland's colonial government, but when conflict arose with Great Britain, Jenifer embraced the Patriot cause.

When, in 1776, a new constitution was framed for the state of Maryland, Jenifer commented on the document's neglect of popular sovereignty: "The Senate does not appear to me to be a Child of the people at Large, and therefore will not be Supported by them longer than there Subsists the most perfect Union between the different Legislative branches."

Like his old friend Benjamin Franklin, Jenifer enjoyed the status of elder statesman at the Convention, which took place from May 25 to September 17, 1787, in Philadelphia, Pennsylvania.

Jenifer used his prestige (as well as humor and reputation as pleasant company) to work for a strong and permanent union of the states by reconciling opposing views and formulating the compromises that made the convention a success.

Business experience gained while managing a large plantation had convinced him that an active central government was needed to ensure financial and commercial stability.

Jenifer was outvoted on this point, but his reaction was to marvel at the delegates' ability to come to agreement on a plan of government: "The first month we only came to grips, and the second it seemed as though we would fly apart forever, however we came as close as friends of eighty years in but days.