John Ten Eyck Lansing Jr. (January 30, 1754 in Albany, New York – vanished December 12, 1829 in New York City), was an American lawyer and politician. He was the uncle of Gerrit Y. Lansing.
Lansing studied law with Robert Yates in Albany, NY and was admitted to practice in 1775. From 1776 until 1777 during the Revolutionary War Lansing served as a military secretary to General Philip Schuyler. Afterwards he was a member of the New York State Assembly from 1780 to 1784, in 1785-86, and 1788–89, being its speaker during the latter two terms. He served New York as a member of the Confederation Congress in 1785. In 1786, he was appointed Mayor of Albany. He represented New York as one of three representatives at the Constitutional Convention in 1787. His intentions at the convention were to follow the wishes of the New York Legislature which had elected him to attend. He was authorized only to amend the existing Articles of Confederation. As the convention progressed, Lansing became disillusioned because he believed it was exceeding its instructions. Lansing believed the delegates had gathered together simply to amend the Articles of Confederation and was dismayed at the movement to write an entirely new constitution. His desire was to see the Articles strengthened giving it a source of revenue, the power to regulate commerce, and to enforce treaties. He joined other prominent Anti-Federalists that strongly opposed Alexander Hamilton, James Wilson and James Madison's notions of a strong centralized national government to replace the Articles. He, Luther Martin of Maryland, George Mason of Virginia and Robert Yates also of New York strongly opposed the newly proposed United States Constitution because they thought it was fundamentally flawed and should be rejected because it infringed on the sovereignty of the independent States and did not do enough to guarantee individual liberty. Both he and Robert Yates walked out after 6 weeks and explained their departure in a joint letter to New York Governor George Clinton. Lansing and Yates never signed the constitution. At the New York Ratifying Convention that followed, he along with Melancton Smith took the lead in the debates as the leaders of the Anti-Federalist majority. Their attempts to prevent ratification ultimately failed by a narrow vote of 30 to 27. He was appointed a Justice of the New York State Supreme Court in 1790 and on 15 February 1798 he was elevated to the post Chief Justice. In 1801, he also became the second Chancellor of New York, succeeding Robert R. Livingston. In 1814 he became a regent of the University of New York.