Can my buyer back out of the deal if the landlord takes too long to approve the assignment?

Usually, yes — but it depends on how your purchase agreement handles landlord consent as a closing condition, not on the lease itself. Purchase agreements for a business purchase and sale commonly make obtaining landlord consent to the lease assignment a condition of closing, often with an outside date by which it must be satisfied. If that condition isn't met in time and the agreement gives the buyer the right to walk away when a closing condition fails, a slow landlord can effectively let the buyer exit the deal.

Whether the buyer can walk away, must extend the deadline, or has other obligations in the meantime (like an exclusivity or deposit provision) depends entirely on how that condition and its timeline were drafted. A poorly drafted or missing consent condition can leave both sides in an uncertain position if the landlord simply stalls.

This is exactly why the consent condition and its deadline need careful drafting before signing, not after a slow landlord becomes a problem. A Treadstone business lawyer can make sure your agreement addresses what happens if approval drags on.