Close family friends declined invite. Is it alright to tell them that I am upset?

If they are close enough with you, I would tell them. Maybe say "I see you declined for my wedding, and while I respect that it's your choice to make, I am hurt because xyz"

Is there a reason they invited other family up that weekend? A graduation? Significant family event? Or does it seem to be more just having family for a visit just because?

I wouldn't tell them you're hurt. You're assuming they didn't save the date. As close as you think you all are, there could be things going on behind closed doors (that they don't want to discuss) that are preventing them from attending. If you feel compelled to reach out, I'd just say you're sorry to hear they can't attend, but that you'd love to make plans to see each other sometime soon.

Agree with Rachael. There may be something personal going on and they may want to discuss it right now, or be around anyone.

No. An invite isn't a summons and no guest owes you an explanation. When you see them again you just say "We're so sorry you can't/couldn't make. you will be/were missed." and move on with conversation.

If you're going to say anything, I would wait until after the wedding. They probably really would like to come to the wedding, and they may have invited this other family up for A weekend and it just happened to be that your wedding weekend is the only weekend this other family could make it work. You don't know all of these "logistics" behind what's going on and it isn't your place to pry if they aren't going to offer up a full on explanation, and it's no use making the family feel more guilty about it than they already do.

I had a few of those. Sent the save the date's out 10 months before, and I swear people used them to schedule something else on that date, not save it. Just had the same problem with my baby shower. My Mom told some guests to mark the date on their calendar, way back around Xmas and they scheduled things, that could have been done other weekends. Oh well ...

I have a family in my life like this. My best friends family who I have known for over 30 yrs. That's a long time. I've attended all of her sisters graduation, birthday parties over the years. So, when I had a huge graduation party for my 22 year old (down syndrome) daughter, who by the ways has become so close to my best friends mom and aunt over past several years, couldn't come to the party (she had plans to go to a casino that wknd) I was super hurt. We had been planning this party for yrs sometimes in the presence of this family. Her sister also didn't make it. My best.friend and her daughter did come. When her mom told me she wouldn't be attending the party at a family gathering on Easter, a wk before the party, I know disappointment was written all over my face ... but I graciously thanked her for letting me know (giving me her rsvp) and told her she would be missed. It took a lot to be gracious in the midst of disappointment. I know I can't compare a grad party to your wedding, but the grad party was a big to do and I put a lot of work into it and was hoping the ppl we loved would be there. I wouldn't go any further than let them know you are sorry they won't be attending and that they will genuinely be missed. I would not go out of my way to call them to tell them this. This family of mine is invited to the wedding. Their daughter/sister is my MOH, so it will be interesting if they come or not. Don't be so sad move on from this.

You can express your disappointment that they won't be able to make it. You can't confront them about it though. It's their right to accept or decline as they choose.

I'd just leave it since it's their choice but remember that in the future when you are speaking with them - could mention that you feel pretty disappointed that they couldn't come

What will you accomplish by saying anything? Their other plans are already made, and being confrontational is not going to make them any more willing to change them. No-- if you want to KEEP these people as "close family friends", a polite "You'll be missed" is as far as you can go.