The Norwich and Worcester Railroad (N&W) was a railroad in the U.S. states of Connecticut and Massachusetts. Its north-south mainline ran between its namesake cities of Worcester, Massachusetts, and Norwich, Connecticut, (later extended to Groton). The Providence and Worcester Railroad (P&W) owns the ex-N&W line and operates freight service.
The railroad was chartered in 1832 in Connecticut, and in 1833 in Massachusetts; the two companies merged in 1836. Construction began in 1835. The line opened between Norwich and Plainfield in 1839, and the full length to Worcester in 1840. An extension to Allyn's Point was completed in 1843 to improve connecting steamboat operations. The line was leased by the Boston, Hartford and Erie Railroad in 1869, and became part of the New York, New Haven and Hartford Railroad (the New Haven) system in 1898. The following year, a second extension to Groton was completed.