<Li> Spencer Breslin as Conrad Walden, Joan's destructive and misbehaved son . </Li> <Li> Dakota Fanning as Sally Walden, Joan's dull, well - behaved, and rule - obeying daughter . </Li> <Li> Kelly Preston as Joan Walden, Conrad and Sally's mother, and a workaholic real - estate agent . </Li> <Li> Alec Baldwin as Lawrence "Larry" Quinn, the Waldens' pompous, lazy, unemployed next - door neighbor . He is revealed to be allergic to cats, steals food from the Waldens and gets away with it, and is determined to both marry Joan for her wealth and send Conrad to military school to straighten up his behavior . </Li>

Who plays the mom on cat in the hat