The premise that jehovah's Witnesses and Mormons are regarded as Christian is open to question, or at least it was in the twentieth century. The idea that the Christian faith is defined by the Nicene Creed has not vanished altogether.

Islam does not accept that Jesus is the Messiah, the word of God, who came from heaven. Neither do they accept what the Bible says about him. They believe Jesus was only a man, a prophet yes, but Muhammad is the last prophet. They deny the death and resurrection of Jesus and say he will come back as a follower of Muhammad. Please edit your question because it does not reflect the beliefs of Islam.

To remove error and understand what the main theological differences are between the Church of Jesus Christ of Latter Day Saints (LDS) and Jehovah's Witnesses, please refer to christianity.stackexchange.com/questions/60930/…

Invalid Question It is impossible to arrive at a valid answer to this question as it is worded. It contains two (2) false premises (presuppositions) that are grossly inaccurate. (1) Mormonism and JW's are not recognized as Christians by mainstream denominations, but as heretical sects, and (2) They do not all believe the same thing! They differ widely on major cardinal truths of Christianity.

Aren't heretics Christians that have important points of doctrine wrong, i.e. still considered Christians? Whereas non-Christians are religions that are based on fundamentally different tenets, such as Hinduism.

From the perspective of a Latter-day Saint your question has a false premise. We most certainly do believe that Jesus is a god. It never ceases to amaze us that anyone believes we don't.

Certainly most Christians who bother to draw lines of classification would treat JW's as heretics (their christology being non-Nicene) but Mormons as non-Christian.

@JBH LDS say Jesus is "a god", the firstborn offspring of a heavenly father and a heavenly mother. What is the name of the god and goddess who procreated a spirit son identified first as Jehovah and then came to earth to be born as a human called Jesus? How many gods are there within LDS theology?

christianity.stackexchange.com/a/14636/23657

@Lesley Is that important to the OP's question? The OP claimed we don't believe Jesus is a god and used that assertion to rationalize their question. Unfortunately ,for the OP, yes, we do. That we don't believe in the trinity dogma you believe in wasn't part of the question. If it should be, then you should be asking the OP to modify their question. If you really want to do is debate whether your religion is better than my religion, you're on the wrong stack.

@yters "Aren't Christians that have important points of doctrine wrong, still considered Christians?" It depends on which doctrine! Christians have widespread disagreement on many issues (especially eschatology). But there is a shared core doctrine that any group who departs from it is considered a separate non-Christian religion branched off from Christianity (if large) or non-christian cult (if small). Catholics and Protestants and Eastern Orthodox and Coptics are all within the "Christian" circle of doctrine, but many Christian-derived religions are outside the circle.

@JBH - Given this question has now been changed to focus on Islam, my reference to the beliefs of LDS would be irrelevant if the OP changed his main question to eliminate LDS and JW's. But he has not. I wasn't making reference to the Trinity, only to the fact that LDS have many gods and goddesses and that is not Biblical. I've already asked the OP to modify his question but he is stuck on the Islamic issue. Perhaps you can convince him to change his question?

Muslim here. We DO consider Jesus to be the Messiah, and sometimes refer to him as "Word of God". But we don't believe he is God's son, in any literal or biological sense. My understanding is that Mormons and Jehovah's Witnesses both believe that Jesus is God's son. To me, that seems like a HUGE difference in our beliefs.

@DawoodibnKareem - I agree, but the sticking point is that Islam says Jesus was only a prophet, and that Muhammad was the final prophet and when Jesus (Isa) returns he will be a follower of Muhammad. Call him the Messiah, but the Bible calls him the Son of God. Christianity is founded on the death and resurrection of Jesus (Isa) but Islam denies that. That is a HUGE difference between Christianity and Islam.

@Lesley Definitely. I agree with you entirely. But the premise of the question is that Mormons and JWs both believe the same as Muslims regarding Jesus, the Txxxxxy and the Bible. And that's absolutely not true. Mormons and JWs accept the Bible as scripture; Muslims do not. Mormons and JWs consider Jesus to be God's son. Muslims do not. Mormons (but not JWs) believe in some kind of Txxxxxxy, although it's a bit different from the "mainstream Christianity" version. Muslims certainly do not.

@JBH The question here is not re "better" but whether LDS beliefs are Christian by any usual understanding of the term. ||WRT the core beliefs of Protestant, RC & Orthodox Christians the LDS church shares essentially no commonality of understanding of Christ or the Father, the relationships of mankind/angels/demons, the relationship of Christ to mankind, or to The Father, or to Satan. Their core beliefs are almost totally different from those of core Chistianity. This MAY not make them wrong per se. But it makes them non-Christian as the term is understood by essentially all other Christians.

@raygrant I think you have a good point in your comment so I didn't delete it, I edited it so it didn't look like you were personally calling out LDS and JW as heretics, but acknowledging the fact that the various Christian denominations do.

I think this is basically the same question christianity.stackexchange.com/questions/24217/… in reverse

@Peter Turner The link you have given explains why Jehovah's Witnesses and Latter Day Saints are considered to be non-Christian. However, the focus of this question seems to have shifted from JW's and LDS to Islam. Since Islam is NOT a Christian denomination I think the OP should either remove Muslims from this question, and delete all references to Islam, or remove JW's and LDS from this question and ask a new question focusing on them only. However, the OP seems reluctant to admit that Islam is not Christian.

The Mormons & JWs emerged in the 1800s in an increasingly secular American society where heretics were not burned & executed as occurred in recent past centuries in Europe. For example Wikipedia says JWs religious activities are banned or restricted in some countries, including China, Russia, Vietnam, and many Muslim-majority countries. It appears this often occurs due their refusal to do military service. I guess this refusal to join the military is closer to Jesus than wanting to join the military.

Jesus is not the central messenger of Islam. Jesus is the central messenger for Mormons and JWs. The doctrine of the Trinity appears to be a later Catholic Church doctrine. Mark 12:31; John 15:15 and John 15:26 give the impression the Father, Son & Holy Spirit are separate things.