"The Sphinx Without a Secret" is a short story by the Irish author Oscar Wilde. It was first published in the newspaper The World in May 1887. It appeared in print again in 1891 as part of the anthology Lord Arthur Savile's Crime and Other Stories.
The story centers around the relationship between a man, Lord Murchison, and a woman, Lady Alroy. Lady Alroy appears to have a mystery connected to her. She refuses to tell Lord Murchison what it is and he is unable to figure it out.
The story's unnamed narrator is sitting at a café in Paris when he suddenly notices his old friend Lord Murchison, whom he has not seen since they were both students together at Oxford ten years earlier. Lord Murchison looks troubled and the narrator deduces that a woman is the cause of his worries. The two men take a cab to a restaurant. Lord Murchison insists that they do not travel in a yellow one. In the cab, Lord Murchison shows his friend a photograph of a beautiful woman with a subtle smile who is wearing furs. He asks his friend if he thinks that the woman looks truthful. The narrator is uncertain. He thinks that she looks like someone with a secret but is unable to tell "whether that secret was good or evil". Lord Murchison refuses to say any more about the woman until after he and his friend have eaten dinner. The narrator holds his friend to his promise after they have finished their meal.
Lord Murchison explains that in London's Bond Street one day, he briefly saw the face of a beautiful woman in a small yellow carriage. For several days afterwards, he looked for her again but was unable to find her. A week later, he was introduced to her at a dinner party at the home of Madame de Rastail. He found out that her name was Lady Alroy, that she was a widow and that she lived in Park Lane. When he said to her he recently saw her in Bond Street, she told him not to speak so loudly because somebody might overhear them. Lord Murchison asked Lady Alroy if he could visit her house. She looked around to check if any other guests were listening before telling him that he could come over the following afternoon.
When Lord Murchison went to Lady Alroy's house at the appointed time, he found that she was not at home. He wrote her a letter, asking if he could see her again. She replied several days later, arranged another time to meet and requested that he not write to her home address again. She told him instead to address all her mail to, "Mrs. Knox, care of Whitaker's Library, Green Street". She added that there was a reason for this but refused to elaborate. Lord Murchison saw Lady Alroy many times, fell deeply in love with her and wanted to marry her. However, he continued to be frustrated by the mystery which surrounded her.
One morning, Lord Murchison happened to see Lady Alroy, with her face veiled, enter what looked like a lodging house on Cumnor Street. She dropped a handkerchief on the doorstep. which was picked up by Lord Murchison, although the lord decided not to spy on her any further. That evening, Lord Murchison went to Lady Alroy's house. She told him that she was happy to see him because she had not been out all day. When he showed her the handkerchief and demanded to know what she had done and who she had seen that day, she replied, "There is nothing to tell you", and, "I have seen no one", before starting to cry. Lady Alroy insisted that she was speaking the truth but Lord Murchison angrily left her home.
Lady Alroy sent Lord Murchison a letter which he sent back unopened. Shortly afterwards, he left the country to spend a month in Norway with a friend. When he returned to London, he read in the newspaper that Lady Alroy had died after catching a chill. Lord Murchison went to the lodging house in Cumnor Street. From the landlady, he found out that Lady Alroy had rented a room there which she went to occasionally. However, the landlady added that Lady Alroy never met anyone else there, she simply sat in her room, read books and drank tea.
Lord Murchison asks his friend if he thinks it is true that Lady Alroy was not seeing another man at the lodging house. The narrator replies that he thinks it is. When Lord Murchison asks for an explanation, the narrator says that Lady Alroy was someone who loved mysteries. However, being "a Sphinx without a secret" with no mystery of her own, she had to invent one. Lord Murchison, however, is not entirely convinced.
- The 1891 anthology Lord Arthur Savile's Crimes and Other Stories also includes the short stories "Lord Arthur Savile's Crime", "The Canterville Ghost" and "The Model Millionaire". The story "The Portrait of Mr. W.H." was not included in the first edition but was added to editions published after 1900.