A writing slate is a piece of flat material used as a medium for writing.

In the 1800s, writing slates were made of slate, which is more durable than paper and was cheap at the time when paper was expensive. It was used to allow children to practice writing. Thin slabs of slate, typically three inches by five (roughly 9 x 12 cm), were also bound into "slate books" for adult use in workplaces.

Slates can be written on using a slate pencil. This is a rod made of soft slate, soapstone, or pressed clay, which makes a thin white line on the slate. Chalk can also be used. The writing can be wiped off with a soft cloth.

Writing slates, although not made of the rock, are still used:

• Scuba divers carry plastic slates and pencils to communicate with other divers, to record facts underwater or read pre-dive plans.
• Proprietary writing slates which protect young children and their clothes from the damage and discolouration potentially caused by paint, pencils and pens are used as toys or educational items.