**Pafnuty Lvovich Chebyshev** (Пафнутий Львович Чебышёв) (1821-1894) was a Russian mathematician. His name is also transliterated as **Tchebycheff** or **Tschebyscheff**.

He is known for his work in the field of probability and statistics. Chebyshev's inequality says that the probability that a random variable is more than *a* standard deviations away from its mean is no more than 1/*a*^{2}. If μ is the mean (or expected value) and σ is the standard deviation, then we can state the relation as:

The Chebyshev polynomials are named in his honor.

In analog electronics there exists a filter family named "Chebyshev filters".

**See also:**

- Chebotarev's density theorem - (algebraic number theory)
- Bienaymé-Chebyshev inequality - (1853|1866)