A soybean cultivar designated M08851 with high yield potential, tolerance to Roundup.TM. herbicide, mid-to-late Group 1 maturity and resistant to race 3 and moderately resistant to race 14 of Soybean Cyst Nematode, further including the plants and seeds of the cultivar M08851, methods for producing a soybean plant by crossing the cultivar M08851 with itself or another soybean plant. The invention also relates to soybean cultivar M08851 further comprising one or more single gene traits, and to methods of producing a soybean having such traits by introgression, transformation or mutagenesis. The invention also includes using the soybean cultivar M08851 to produce other soybean cultivars, breeding lines, and progeny.