Beatrice Muriel Hill Tinsley (1941 - March 23, 1981) was an astronomer and cosmologist whose research made fundamental contributions to our understanding of how galaxies evolve with time.

She was born Beatrice Hill in England in 1941, and emigrated to New Zealand with her family following World War II. After graduating from Canterbury University with a Masters degree in physics, she moved to Austin, Texas with her husband, physicist Brian Tinsley, where she completed her Ph.D in 1966. Her Ph.D dissertation is entitled Evolution of Galaxies and its Significance for Cosmology. At the University of Texas at Austin, and later at Yale University, Tinsley completed pioneering theoretical studies of how populations of stars age and affect the observable qualities of galaxies. She also collaborated on basic research into models investigating whether the universe is closed or open. Her galaxy models also led to the first approximation of what protogalaxies should look like.

In 1974, her achievements led to her being awarded the Annie J. Cannon Award in Astronomy from the American Astronomical Society and the American Association of University Women.

Tinsley's career was cut short when she died of cancer in 1981.

In 1986 the American Astronomical Society established the Beatrice M. Tinsley Prize for outstanding creative contributions to astronomy or astrophysics.

A selection of her publications includes:

• Correlation of the Dark Mass in Galaxies with Hubble type, 1981, Royal Astronomical Society, Monthly Notices, vol. 194, p. 63-75
• Relations between Nucleosynthesis Rates and the Metal Abundance, 1980, Astronomy and Astrophysics, vol. 89, no. 1-2, p. 246-248
• Stellar Lifetimes and Abundance Ratios in Chemical Evolution, 1979, Astrophysical Journal, Part 1, vol. 229, p. 1046-1056
• Colors as Indicators of the Presence of Spiral and Elliptical Components in N Galaxies, 1977, Publications of the Astronomical Society of the Pacific, vol. 89, p. 245-250
• Surface Brightness Parameters as Tests of Galactic Evolution, 1976, Astrophysical Journal, vol. 209, p. L7-L9
• The Color-Redshift Relation for Giant Elliptical Galaxies, 1971, Astrophysics and Space Science, Vol. 12, p.394