Quick answer: no — Massachusetts does not let a surviving spouse add a deceased spouse's unused threshold to their own. Run your own numbers in the Massachusetts estate tax calculator.
One threshold per spouse, no exceptions
The marital deduction is the trap, not the fix
Transfers between spouses generally aren't taxed at the first death. But that's exactly what causes the problem: if the first spouse leaves everything outright to the survivor, that spouse's own $2,000,000 threshold goes completely unused, with no way to recover it when the survivor later dies.
The standard workaround: a credit shelter trust
Massachusetts couples typically use a credit shelter (bypass) trust to hold assets up to the exemption amount when the first spouse dies. Those assets pass outside the surviving spouse's own taxable estate, so the couple ends up using both $2,000,000 thresholds instead of losing one.
A QTIP election can work alongside it
Some families also use a Qualified Terminable Interest Property election, which lets the surviving spouse benefit from trust assets during their lifetime while still keeping those assets out of their own taxable estate — a flexible tool your attorney can pair with a credit shelter trust depending on the estate's specifics.
A local probate attorney can review your estate — many offer a free consultation.
For married couples with a combined estate above $2,000,000, getting this piece of the plan right is often the single most consequential decision in the whole estate plan.