Almost certainly not by his own hand, but did he order their deaths, or let it be known to some obliging courtier or knight that he wouldn’t mind it? It’s a longstanding question in English history, and came up recently in the “Henry VIII: Nice guy or psychopath?” thread. I couldn’t find a SDMB thread solely devoted to it.
Richard III had motive (and then some), means and opportunity; I think he did it, although we’ll probably never know for sure.
What say you?
Except Henry VII had motive, means and opportunity as well.
Absolutely. I am personally of the opinion that Richard III beat him to the punch, but the only thing that kept Henry VII from killing them was that he couldn’t kill them twice ;).
ETA: But this one really is pretty impossible to unravel. As I’ve argued before I think Occam’s Razor favors ( or disfavors ) Richard III. But it is pretty likely somebody did and both of the main suspects were easily ruthless enough for the job. It’s partially the same reason they were both good king material.
I don’t think he did, because I don’t think he would have done it the way he was supposed to have done it. I think it would be supremely stupid of him to have murdered them in secret. What does that accomplish? If no one knows they are dead, then anything he might fear from them being alive, like an uprising in their favor, can still happen. I think if he had caused them to be murdered, he would have had them suffocated, then displayed the bodies, and claimed they’d died of a fever, or sweating sickness, or something, and had royal funerals for them. Richard didn’t know he would reign only three years; as far as he knew, he could reign for forty, and would probably be asked about the boys at some point.
Henry VII benefited more from them disappearing mysteriously. If they were newly murdered, but he wanted people to believe Richard had killed them several years earlier, he couldn’t very well display the bodies.
It’s also significant, I think, that Henry didn’t conduct a search for them. If they were genuinely missing, suspected murdered, and Henry genuinely had nothing whatsoever to do with it, I think he would have searched high and low for the bodies. They were after all, his brothers-in-law, and Henry had more to fear from an uprising in their favor, since he had legitimized them. Plus, Henry had to worry about pretenders (which did happen). If it had been in Henry’s power to produce bodies, I think he would have, but clearly, he couldn’t produce two very fresh bodies and blame their deaths on Richard.
So no, I don’t think Richard did it, and yes, I think Henry did. Henry got rid of an awful lot of other people. The princes would have been just two more, more or less, and he’d probably lost count.
Absolutely. I’ll say what I’ve said before on this topic: it would have been par for the course for either monarch to have done it. Renaissance princes were not exactly known for restraint in such areas. 
It is a very amusing aspect of Tudor propaganda to make out Dick 3 as the bad guy for murdering off inconvenient relations, considering how adept the Tudors were later to be at doing exactly that … !
One thing that might be of interest would be a proper forensic examination of the two skeletons which were found buried in the Tower in the 19th century. The two princes were just on the verge of puberty, and the changes to the body during puberty apparently have some impact on the skeletal structure. It therefore might be possible to get a rough estimate of the ages of the two individuals at death.
That in turn may point to either Richard or Henry. If they were pre-pubescent, then Richard; if they were older, then Henry.
Exactly. And the two skeletons were pre-pubescent. Also, there was a velvet blanket, and velvet was unknown in England until the reign of Edward IV.
Only two pre-pubescent children (male or female) were in the tower between the reign of Edward IV until the discovery of the bodies: the two princes.
Case closed.
Someone once said that your opinion on Richard III’s guilt depended on if you read Daughter of Time at an impressionable age. I did. So, I think he was innocent. 
FWIW, in Mary Kay Penman’s historical novel The Sonne in Splendour* – which portrays Richard as the best of his family – the Duke of Buckingham has the little princes killed on his own malicious initiative, and Richard is horrified and cuts off his head for it. Also, Richard is sincerely convinced that Edward IV’s premarital “plight-troth” to a woman other than Queen Elizabeth renders his marriage to Elizabeth invalid and puts their sons out of the line of succession.
Nah. Doctor Who explained in the audiobooks the real truth: The Princes were in fact girls, and Edward V never told Richard the truth. When he found out, he had to remove the girls and become King, for the sake of the stability of the realm. The Princes(ses) became bar wenches, so it all worked out.
I’ve always suspected that Our Lady the King’s Mother (Margaret Beaufort Tudor Whatever Whatever) had Buckingham do it on Henry VII’s behalf so that he could increase his (dubious) claim to the throne by marrying Elizabeth of York. Alive and legitimate, they would be the rightful heirs. Dead and legitimate makes Elizabeth the legitimate Plantagenet heir.
Yes, I agree. Not that RIII was incapable of doing such a thing, but he really had far less motive than HVII. After all, RIII had the princes declared illegitimate by act of Parliament, and there was little unrest or attempts to put them on the throne.
HVII on the other hand would have had to kill them.
If RIII had killed them, why didnt HVII make a big noise about the murders right after taking the throne? He was plagued by Pretenders, whilst RIII was not. HVII had a great motive for killing them- or if he had found RIII did- making it very public.
The bones were removed and examined in 1933, by the archivist of Westminster Abbey, Lawrence Tanner; a leading anatomist, Professor William Wright; and the president of the Dental Association, George Northcroft. By measuring certain bones and teeth, they concluded the bones belonged to two children around the correct ages for the princes.[2] The bones were found to have been interred carelessly along with chicken and other animal bones. There were also three very rusty nails. One skeleton was larger than the other, but many of the bones were missing, including part of the smaller jawbone and all of the teeth from the larger one. Many of the bones had been broken by the original workmen.[22][23] The examination has been criticised, on the grounds that it was conducted under the presumption that the bones were those of the princes and concentrated only on whether the bones showed evidence of suffocation. Thus no attempt was even made to determine whether the bones were male or female.[2]
*
2. No, King Richard II of England directed in his will that his body should be clothed in velveto in 1399.
Thereby, you are wrong on all three points.
Remember- HVII had no blood claim to the Throne.
And also, “Why I, in this weak piping time of peace, have no delight to pass away the time, except to spy my shadow in the Sun, and descant on mine own deformity!”
Fuck the Jacobites, let’s start a movement for a Plantagenet Restoration!
Also note, if RIII had them killed, he would have let it been known they were dead.
I think if they’d died in a way to make it look like natural causes, he would have announced their deaths.
If they died via violence, then it was in his best interest to let them just quietly disappear so no questions would be asked. The Lancasters and the Yorks had been battling it out for a long time, and Henry Tudor was not the only one interested in that throne, and Richard was not well loved.
The Tudorites claim RIII had them killed by suffocating, so they’d look pretty natural.
The Tudorites weren’t there - and if you aren’t going to credit them for knowing that it was Richard, why would you credit them with knowing it was suffocation? The whole point of this is no one knows how they died. They might have died of old age in Scotland for all we know (unlikely, they were too dangerous alive). They may have died of illness, or fallen down the stairs. What we know is they went into the Tower, then at some point, disappeared from History.
Pick your poison, there are a few lines to choose from: