Which to See First - Pompeii/Herculaneum or the Museum of Archeology in Naples?

That is an interesting question. I haven't made it to the museum in Naples yet, but have been to Pompeii and Huerculaneum. In memory, I think visiting the museum first, will give you the art, and once at the sites, you can see how they might have fit in situ. There are some artifacts at the sites, but not the best, and it would be harder to visualize what the rooms looked like not knowing what they would have put in them. Of course, if you don't have that ability to visualize, then it might not matter.

Last year on the South of Italy tour we visited Pompeii before the museum. That was because of the tour itinerary. But it also made sense in that you can see and understand the physical towns so when you see the artifacts you visualize where they were and how people lived.

I recommend seeing the spectacular Museum of Archaeology in Naples first before Pompeii/Herculaneum. The Museum houses many original artifacts from Pompeii and displays them very clearly. I spent 2 nights in Naples and took the train to Pompeii for the day. I didn’t have time for Herculaneum.
I was not on a tour, I used Rick’s guidebook and he recommended the itinerary I took as a solo traveler. On the South Italy tour, the guide likely gives you lots of information.

Depends on your itinerary and if you are traveling to/from Naples. My wife and I were in Amalfi and took a private shuttle service from to Mt. Vesuvius, Pompeii, and Herculaneum en route to Naples all in one day. Full day for sure and I would have liked about one hour more at Pompeii, but well worth it for the ground we covered. We toured the museum after the next day after spending the morning viewing the catacombs which was another great tour. I think it's a personal preference if you want to see the amazing artifacts in the museum first or the ruins first. For us, it was a logistical choice so we did not waste time backtracking.

If it is in Hot Weather...it's a good idea to visit the archeological sites in the cool of the morning. The Museum probably has climate control for the artifacts. Edit: or is more naturally cool because of stone construction.

My recollection is that the Museum was cooled by the fact that it is a large stone building. I don't recall any great air conditioning system in operation.

I can tell you that the museum has no a/c and in July it was dreadfully hot.

That said, we went to museum first because that is the way our schedule worked out. The next year we went to Minoan ruins In Greece before seeing the frescos in Athens.

I think I liked visiting the archeological site before the museum better.

I debated this until it turned out I had no choice - one of my 2 days was a museum closed day. So I went to the museum AFTER Herculaneum. I actually think it worked well - I could visualize the objects in the museum in the space.

I don’t think it actually matters all that much though.

Go with how you feel that day. Either plan works.
If approached by a licensed tour guide while in line to buy a ticket for Herculaneum, do it. I was a solo traveler when approached and I quickly convinced a few others in line to join in. The cost was nominal and Herculaneum came alive again with the guide.

On your first opportunity to see the Pompeii sight, if the weather is good, see it, and then the museum. If it is raining or there is other unpleasant weather, but if the weather is supposed to be better the next day, see the museum first.

I saw the Pompeii sight the day before I saw the museum. In general, I prefer to learn some background information before seeing major sights. Before my trip, I read a big coffee-table sized book containing half color illustrations, and small print, that was mainly about Pompeii, and a little bit about Herculaneum and possibly another nearby sight. In general when everything else is equal I go to outdoor sights before museums. If you don't have advance tickets, make your decision at the last minute based on the weather.

I saw the sites first and then the museum. I probably would have preferred to see the museum first, but I didn’t actually get the opportunity until a few years after I had seen both sites. The museum is definitely one of my favorites!

I think there is no 'wrong' order.

I would do whichever makes better logistical sense.

We stayed in Sorrento and visited Pompeii and Herculaneum from there. We went to the museum during the last couple of days that we spent in Naples before our flight. Logistics drove the decision. Having seen the sites first, the artifacts felt connected to what we had already seen and perhaps made a stronger impression. As someone said previously, it was easier to imagine the artifacts in their original homes.

We did self-guided tours at both sites. With a do-over, and a bit more budget than I had before, I would go with a guide, at least to Pompeii.

Thanks for all the helpful comments. I may end up at the museum before and after visits to the sites!

To the future.

I went first to Herculaneum, then to Pompeii and lastly to the museum. I don't remember having any reason to go in that order. Going to Herculaneum first turned out to be good because it was a rainy day. The site is much easier to walk through and I was able to find shelter when the rain was hardest. After that I was grateful that I visited Pompeii on a sunny day; I can't imagine how hard it would be to walk on some of the stone streets when they are wet - it's hard enough when they're dry. The 2 sites are very different. Pompeii is more spectacular and much bigger, but you get a better feel for what it was like to live in a town in Herculaneum, so I would probably recommend going there before Pompeii. I don't think it would have made any difference to me if I'd visited the museum before the archaeological sites.