Sort of. The general trend over the course of the Middle Ages was that 'attitudes towards Jews changed not only in intensity but also in character from 1096 to 1400, developing from a relatively simple and direct religious antagonism to irrational fears.'(1). Some people could see this shift occurring and tried to prevent it, but this took a rather odd form. The literature in defence of Jews in the Middle Ages wasn't that people shouldn't be antisemitic as such - we would almost certainly consider the views espoused by these 'defenders' as antisemitic today - but that they did not deserve to be physically harmed. Take Bernard of Clairvaux, the most famous and influential preacher of the mid-12th century, as an example. Bernard was definitely antisemitic, but in preaching the Second Crusade he had to face the fact that crusades almost always resulted in outbursts of antisemitic violence across Europe, even though that was not the intention at all. Bernard had to explain why the northern pagans were fair game, but Jews were not. This is how he 'defended' the Jews:

For the rest, not I but the Apostle warns you, brethren, not to believe every spirit. I have heard with great joy of the zeal for God's glory which burns in your midst, but your zeal needs the timely restraint of knowledge. The Jews are not to be persecuted, killed, or even put to flight. Ask anyone who knows Sacred Scripture what he finds foretold of the Jews in the Psalm. 'Not for their destruction do I pray,' it says. The Jews are for us the living words of Scripture, for they remind us of what our Lord suffered. They are dispersed all over the world so that by suffering for their crime they may be everywhere the living witnesses of our redemption. Hence the same Psalm adds, 'only let thy power disperse them.' And so it is: dispersed they are. Under Christian princes they endure a hard captivity, but 'they only wait for the time of their deliverance.' Finally, we are told by the Apostle that when the time is ripe all Israel shall be saved. But those who die before will remain in death... If the Jews are utterly ground down, what will become of our hope for their promised salvation, their eventual conversion? If the pagans were similarly subjugated to us, then, in my opinion, we should wait for them rather than seek them out with swords. But as they have now begun to attack us, it is necessary for those of us who do not carry a sword in vain to repel them with force. It is an act of Christian piety both to 'vanquish the proud' and also to 'spare the subjected', especially those for whom we have a law and a promise.

This was generally as far as defence of Jews went in the majority of discourse surrounding their treatment. People believed that God wanted the Jews subjugated but not destroyed to remind Christians of what they would be like without Christ, and so that Christians could hope for their redemption. If nothing else, Jews were seen as an essential component of the apocalypse, so they could not be wiped out. As defences go it's a pretty twisted one, but it's probably better than being murdered.

As for actions, there are definitely instances of people acting to defend Jews. There were also some protections in law, depending on the ruler. The French monarchs were infamously antisemitic and persecuted Jews intensely from the 12th century onwards, often to raise money for crusades. But in England the situation was very different. Whilst both England and France regarded Jews as property of the king (and I do mean property; as in things for the king to do as they wished with), from Henry I to Richard I this status actually gave the Jews a protected status. After all, they were the property of the king - you wouldn't walk into the king's bedroom and smash all his furniture, so you wouldn't kill his Jews either. That being said, Henry II and Richard I genuinely seemed to have cared for the Jews of their kingdom; Jewish communities were given their own charters. You can read one from 1190 here. When Richard I embarked on the Third Crusade, he had created special protections for Jews, and commanded sheriffs to grant them the use of royal castles for protection in the event of violence. The Jews of Lincoln basically lived in the castle there for the duration of the crusade, as the other locals were very hostile to them. When an antisemitic riot in York killed the city's Jewish community, Richard ordered that an army march on the city and execute the ringleaders for treason. Frederick Barbarossa issued similar laws against antisemitic conduct, also for the Third Crusade, had people who harmed Jews put to death, and rode on horseback with a rabbi through Mainz to emphasise the strong relationship between himself and the Jewish community there following an antisemitic riot.

In England, there was a sort of chief rabbi of the crown, who was effectively put in charge of England's Jewish communities. This is the letter of safe passage granted to one of them:

John, by the grace of God... To all his faithful ones to whom the present letters may come both beyond the sea and this side of it, greeting. We command and order you that through whatever towns and places Jacob, presbyter of the Jews, our dear friend, may pass you shall cause him to pass through and be conducted safely and freely with all belonging to him, nor allow any hindrance, hurt, or injury to be done to him any more than to ourselves. And if any presume to transgress in any point that you shall cause him to make up for it without delay.

This is a clear example of a Jew being defended against the (very likely) antisemitic conduct, which could often be violent, by the crown. King John gradually became more antisemitic over the course of his reign, however.

Finally, there were genuinely some people and places who genuinely and altruistically welcomed Jews as part of the wider community. Many monasteries and theologians (including Bernard of Clairvaux's predecessor as abbot) consulted with rabbis to help their understanding of books from the Old Testament, for example. See also the example of St. Edmunds Abbey. The local chronicle records that:

Jews, I say, for to them William the sacristan was said to be a father and a patron. They used to enjoy his protection, and had free entrance and exit, and often went through the monastery, wandering through the altars and around the shrine while the solemnities of the Mass were being celebrated. And their moneys were placed in our treasury in the charge of the sacristan, and, what was more absurd, their wives and little ones were received in our refectory in time of war.

Note "used to enjoy his protection". Ten years later Jews were barred from the abbey after William was deposed by a rival, with attitudes toward the Jews being a central issue in the whole affair. Clearly, the trajectory of public opinion was not in favour of Jews, but there were those who sought to protect them and defend them through law, military force, and community spirit.

(1) Langmuir, Gavin I. "The Jews and the archives of Angevin England: Reflections on medieval anti-semitism." Traditio 19 (1963): 183-244.