Margaret Knight (1838 - 1914) was an american inventor. A cotton mill worker from the age of nine through her teens, Knight invented a machine that folded and glued paper to form the brown paper bags familar to shoppers today.

Knight built a wooden model of the device, but needed a working iron model to apply for a patent. A man working in the machine shop where Knight's iron model was being built stole her design and patented the device. Knight filed a successful patent interference lawsuit and was awarded the patent in 1870

With a Massacusetts business man, Knight established the Eastern Paper Bag Co. and received royalties.

Knight received patents for several industrial machines, including a rotary motor.

Knight's original box-making machine is in the Smithsonian Museum in Washington, D.C.