What is the Islamic ruling if a man marries in secret without telling his family?
Or a girl marries without telling her family?
Man's secret marriage if the marriage has fulfilled the conditions and corners is the true in sharee'ah (I mean guardian, two witnesses, the couple, the formula).
It is true, provided that the reservation of rights in dividing, inheritance, and the rest of the rights.
But marriage of women is not aware of her family, they are losing a condition of marriage, which is the guardian
The Prophet says:
عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " أَيُّمَا امْرَأَةٍ نُكِحَتْ بِغَيْرِ إِذْنِ وَلِيِّهَا فَنِكَاحُهَا بَاطِلٌ فَنِكَاحُهَا بَاطِلٌ فَنِكَاحُهَا بَاطِلٌ
Aishah narrated that: The Messenger of Allah said: "Whichever woman married without the permission of her Wali her marriage is invalid, her marriage is invalid, her marriage is invalid. [Jami` at-Tirmidhi]
So that indicate the marriage without a guardian (wali) and two witnesses is invalid.
If the guardian wants to prevent women from their right to marry of her efficient, she can submit a request to the judge,then the judge takes the guardianship and marry her; except it her marriage is not true.