Answered by Shaykh Yūsuf Badāt
If a girl and boy accept each other as husband and wife with only Allāh as a witness, is that considered a valid nikāh?
Jazāk Allāh Khayr/ Thank you for your question.
In order for an Islamic nikāḥ/ marriage to be valid, the following conditions are required:
- Consent of both parties marrying (offer and acceptance)
- At least two Muslim witnesses
- Bridal gift (mahr) from the groom to the bride
- Permission for the bride from her guardian
Since the above mentioned conditions are not found in the described scenario, such a marriage would be incomplete and invalid.
And Allāh Knows Best