walking tours by local guides in Madrid

In 2016 I took a walking tour offered by the tourist office. The cost was modest and I enjoyed the tour. The local tourist office is always my first stop for a walking tour--except in London, where I use London Walks.

Check on Trip Advisor. First will come the tours offered by Viator, then to the left of your screen, you will see a catagory - All Tour Operators. This takes you to the tours that are not being sold by Viator or tours that have a website where you can book directly. Viator is just a reseller.
Some tourist infos only sell their own tours, where others are true tourist info places offering information about all tours that might be on offer. This is easily checked online.
You could also just use Google to find tours. If you don't click on the Viator or TA ads, you will find other tours.

Also check 'Experiences' at www.airbnb.com. I found very affordable walking tours for Seville and Granada for September.

Experiences Air BnB are like Viator, they are re-sellers and making those tour providers pay a hefty 25-30% commission.

hey hey janet
lots of changes with travel in the "several years" you were in portugal.
you could email the university/school to see if they offer that service, stop at the tourist koisk in a piazza and ask what they offer.
many tours have raised there tours since pandemic trying to catch up with trying to survive. i'm sure you can understand, it's going on here in the states and canada, supply and demand, many left and having tough times hiring people, the cost of going to classes to become driver/guide in europe. the exchange rate is even, in our favor. what prices were you hoping for?
withlocals.com/ madrid
many different tours, you do research and see what you like. we used them a few times in other cities without any issues.
eatwith.com
tastings, cooking classes, lunch/dinner in residents places
discoverwalks.com
madrid, check out the different tours they do and pick whatever floats your boat
getyourguide.com
madrid
hope this helps you out looking for walking tours. have a great time and enjoy
aloha

We’ve always used the guides recommended in RS guides and have been thrilled with the results!

We just booked a walking tour with Stephen of the Wellington Society, in Rick’s book. We are going in October.

We did a very engaging tour of the Reina Sophia museum with Rick’s “friend and fellow tour guide” Federico Garcia Barossa (www.spainfred.com. I contacted him directly, and explained what I wanted, which was not what’s listed on his site. He was fine with that.

He was a real gem.

I agree with the replies above and will add just two ideas: Context Travel https://www.contexttravel.com/cities/madrid

and check with the Atheneum to see if they have something that works for you, or can connect you

https://www.ateneodemadrid.com/eventos/

Note these are both relatively highbrow options, not for general highlights.