I am licensing my software to an Israeli company. Will they withhold tax on my royalty payments?

Almost certainly yes. Royalty payments to non-residents for software licences, patents, or know-how are subject to Israeli withholding tax — typically 25% under domestic law. Many Israeli companies help their foreign licensors obtain reduced-rate certificates, but the legal obligation to obtain the certificate rests with you as the recipient. Review your licence agreement to see whether it addresses withholding tax and whether the gross or net amount is payable.