The 18th New Brunswick Legislative Assembly represented New Brunswick between June 24, 1857, and May 14, 1861.
The assembly sat at the pleasure of the Governor of New Brunswick John Henry Thomas Manners-Sutton.
James A. Harding was chosen as speaker for the house. In 1859, John M. Johnson was chosen as speaker after Harding resigned his seat.
| Electoral District | Name |
|---|---|
| Saint John County | Richard Wright |
| John W. Cudlip | |
| Robert D. Wilmot | |
| John H. Gray | |
| York | Charles Macpherson |
| John McIntosh | |
| John C. Allen | |
| Charles Fisher | |
| Westmorland | Albert J. Smith |
| James Steadman | |
| Robert K. Gilbert | |
| Bliss Botsford | |
| Kings | Edwin A. Vail |
| Walter B. Scovil | |
| Matthew McLeod | |
| Queens | Samuel H. Gilbert |
| John Ferris | |
| Charlotte | Arthur Hill Gillmor |
| John McAdam | |
| James Brown | |
| James Watson Chandler | |
| Northumberland | Richard Sutton |
| George Kerr | |
| Peter Mitchell | |
| John M. Johnson | |
| Sunbury | William E. Perley |
| David Tapley | |
| Kent | Francis McPhelim |
| Lestock P. W. DesBrisay | |
| Gloucester | Joseph Read |
| William End | |
| Carleton | Charles Connell |
| Charles Perley | |
| Restigouche | John McMillan |
| John Montgomery | |
| Albert | Abner R. McClelan |
| John Lewis | |
| Victoria | James Tibbits |
| Charles Watters | |
| Saint John City | Samuel Leonard Tilley |
| James A. Harding |