It's a shame that the DataGridViewTextBoxColumn class doesn't allow you to set the casing so that you can restrict user input to all upper or lower case letters. Fortunately, it's actually pretty easy to create a custom column class to do just that. public class DataGridViewUpperCaseTextBo... : DataGridViewTextBoxColumn { public DataGridViewUpperCaseTextBo...() : base() { CellTemplate = new DataGridViewUpperCaseTextBo... } } public class DataGridViewUpperCaseTextBo... : DataGridViewTextBoxCell...