Opinion of handwriting expert under the law of evidence in India is:

The opinion of a handwriting expert is relevant under section 39 of the Bharatiya Sakshya Adhiniyam, 2023, and the court may also compare writings itself under section 72 (formerly sections 45 and 73 of the Indian Evidence Act, 1872). It is "Relevant but not the sole determinant of genuineness of the document": the court weighs the expert's reasons along with the other evidence, though Murari Lal v. State of M.P. (1980) holds that there is no inflexible rule that expert evidence must always be corroborated. It is therefore neither irrelevant nor conclusive.