While there are as many as 7 different substitutes for dill weed, not all of these have a similar flavor to the herb in question. There are 2 different herbs that are similar in taste and appearance to dill, and which make for an excellent last minute replacement if you haven’t got any dill weed in your store cupboard.
The first herb that tastes and appears similar to dill is fennel. This herb has very similar leaves to dill weed, so you could be forgiven for mistaking one for the other at a glance. Fennel has a more aniseed flavor, but this does taste quite similar to the more potent varieties of dill. Fennel in particular makes for a great garnish substitute for dill because of how similar they appear.
Tarragon would be our next choice in terms of similar flavor. This herb is also more resilient than dill, so can be added earlier in the cooking process. Fresh tarragon can be used in the same quantities as fresh dill.