Lady Constance Keeble (née Threepwood, later Schoonmaker) is a recurring fictional character in the Blandings Castle stories by British comic writer P. G. Wodehouse, being Lord Emsworth's most formidable sister, a strikingly handsome woman, with a fair, broad brow, and perfectly even white teeth.
She endeavours in vain to persuade her brother Lord Emsworth to dress more suitably, and to pay attention to important matters such as the family, rather than his garden and his beloved pig, Empress of Blandings.
However, such matters pale in comparison to the embarrassment that could be caused by her brother Galahad Threepwood publishing his scandalous reminiscences; to prevent this, she is willing to allow the marriage of her nephew Ronnie to a chorus-girl, in Summer Lightning.
She is good friends with Sir Gregory Parsloe-Parsloe, with whom she conspires to prevent the publication of Galahad's memoirs, and also with Rupert Baxter, a man she considers most capable and on whom she calls whenever she is in dire need of practical assistance.
In her youth, she had a bit of a thing with Alaric, the Duke of Dunstable, with whom she was often found whispering in conservatories or being the last back from picnics, but she later questions his sanity, even calling in Sir Roderick Glossop on one occasion to have him analysed.