Any process that stops, prevents, or reduces the frequency, rate or extent of B cell differentiation.
Comment:
Note that immunologists typically use the word 'development' to refer to cells of B or T cell lineages undergoing the process that GO describes as 'cell differentiation'.
Synonyms:
exact_synonym:
down regulation of B cell differentiation; downregulation of B cell differentiation; negative regulation of B lymphocyte differentiation