I am on an H1-B visa, with my wife on an H4. Can we claim a deduction on our joint tax return for a charitable donation that was made in my wife's name (she already has a SSN from a previous stay in the US)? Many thanks, G.

Yes. If you are resident aliens (otherwise you would not b able to file a joint return).The donation would only affect your return if your itemized deductions are higher than the standard deduction.