Helmuth James Graf von Moltke (11 March 1907 – 23 January 1945) was a German jurist, a member of the opposition against Adolf Hitler in Nazi Germany, and a founding member of the Kreisau Circle resistance group. He was the great-grandnephew of Helmuth von Moltke the Elder, the victorious commander in the Austro-Prussian and Franco-Prussian Wars, and the owner of the Kreisau Estate in Prussian Silesia.

Helmuth James Graf von Moltke was born in Kreisau (now Krzyżowa, Poland) in the Province of Silesia. His mother, Dorothy (née Rose-Innes), was a South African of British descent, the daughter of Sir James Rose-Innes, the highest judge in the Union of South Africa. Moltke's parents were members of the Christian Science church, and his father was a Christian Science practitioner and teacher and one of the translators of the German edition of the Christian Science textbook, Science and Health with Key to the Scriptures by Mary Baker Eddy.

From 1927 to 1929, Moltke studied legal and political sciences in Breslau, Vienna, Heidelberg, and Berlin. In 1931 he married Freya Deichmann, whom he met in Austria. In 1928 Moltke became involved with college teachers and youth movement leaders in the organization of the Löwenberger Arbeitsgemeinschaften  (Löwenberg Labour Community) in which jobless young workers and young farmers were brought together with students so they could learn from each other. They also discussed civics, obligations, and rights. In Kreisau, Moltke set aside an unused part of the estate for farming startups, which earned him harsh criticism from neighbouring landowners. In 1934, Moltke wrote his junior law examination. In 1935, he declined the chance to become a judge because he would have been obliged to join the Nazi Party. Instead, he opened a law practice in Berlin. As a lawyer dealing in international law, he helped victims of Hitler's régime emigrate, and traveled abroad to maintain contacts. Between 1935 and 1938, Moltke regularly visited Great Britain, where he completed English legal training in London and Oxford.

In 1939, World War II began with the German invasion of Poland. Moltke was immediately drafted at the beginning of the Polish campaign by the Abwehr —specifically, the High Command of the Armed Forces (Oberkommando der Wehrmacht—OKW), Counter-Intelligence Service, Foreign Division—under Admiral Wilhelm Canaris, as an expert in martial law and international public law. Moltke's work for the Abwehr mainly involved gathering insights from abroad, from military attachés and foreign newspapers, and news of military-political importance, and relaying this information to the Wehrmacht. He maintained the connection between the  OKW and the Foreign Office, but above all to provide appraisals of questions of the international laws of war. In his travels through German-occupied countries, he observed many human rights abuses, which he attempted to thwart by insisting that Germany observe the Geneva Convention (it continued not to) and through local actions in creating more benign outcomes for local inhabitants, citing legal principles. In October 1941, Moltke wrote, "Certainly more than a thousand people are murdered in this way every day, and another thousand German men are habituated to murder... What shall I say when I am asked: And what did you do during that time?" In the same letter he said, "Since Saturday the Berlin Jews are being rounded up. Then they are sent off with what they can carry.... How can anyone know these things and walk around free?" Moltke hoped that, with his appraisals, he could have a humanitarian effect on military events, and was supported in this by anti-Hitler officers such as Canaris and Major General Hans Oster, Chief of the Central Division. During Nazi Germany's war with the Soviet Union, Moltke wrote a controversial opinion urging Germany to follow both the Geneva Convention and the Hague Convention, in order to comply with international law and to promote reciprocal good treatment for German prisoners of war; however he was overruled on the grounds that Russia was not a signatory to the agreements, with Field Marshal Wilhelm Keitel describing the Geneva Convention as "a product of a notion of chivalry of a bygone era." He further acted on his opposition to the brutalities of Nazism by ordering deportation of Jews to countries which provided safe haven, and by writing reports emphasizing the psychological problems German soldiers developed after witnessing and participating in mass killings of Jews and Eastern Europeans. Having access to this information, Moltke began to oppose both the war, and the entire program of the Nazi party.

Moltke also surreptitiously spread the information to which he was privy, regarding the war and the concentration camps, to friends outside the Nazi party, including members of the resistance in occupied Europe. Declassified British documents reveal that he twice attempted to contact British officials, including friends from Oxford, offering to "go to any length" to assist them; however the British refused the first time, confusing him with his uncle, the German ambassador to Spain, and replied to the second offer by asking for "deeds" rather than "talk". Moltke possessed strong religious convictions and in a 1942 letter smuggled to a British friend Lionel Curtis, Moltke wrote: “Today, not a numerous, but an active part of the German people are beginning to realize, not that they have been led astray, not that bad times await them, not that the war may end in defeat, but that what is happening is sin and that they are personally responsible for each terrible deed that has been committed - naturally, not in the earthly sense, but as Christians”. In the same letter, Moltke wrote that before World War II, he had believed that it was possible to be totally opposed to Nazism without believing in God, but he now declared his former ideas to be "wrong, completely wrong". In Moltke's opinion, only by believing in God could one be a total opponent of the Nazis.

In Berlin Moltke had a circle of acquaintances who opposed Nazism and who met frequently there, but on three occasions met at Kreisau. These three incidental gatherings were the basis for the term “Kreisau Circle.” The meetings at Kreisau had an agenda of well-organized discussion topics, starting with relatively innocuous ones as cover. The topics of the first meeting of May, 1942 included the failure of German educational and religious institutions to fend off the rise of Nazism. The theme of the second meeting in the autumn of 1942 was on post-war reconstruction, assuming the likely defeat of Germany. This included both economic planning and self-government, developing a pan-European concept that pre-dated the European Union by nearly sixty years, summarized in documented resolutions. The third meeting in June, 1943 addressed how to handle the legacy of Nazi war crimes after the fall of the dictatorship. These and other meetings resulted in “Principles for the New [Post-Nazi] Order” and “Directions to Regional Commissioners”, works, which Moltke asked his wife, Freya, to hide in a place that not even he knew.

Moltke opposed the assassination of Hitler. He warned that if one succeeded, Hitler would become a martyr, whereas if one were to fail, it would expose those few individuals among the German leadership who could be counted on to build a democratic state after the collapse of the Third Reich. On July 20, 1944 there was an attempt on Hitler's life, which the Gestapo used as a pretext to eliminate perceived opponents to the Nazi regime. In the aftermath of the plot some 5,000 of Hitler's opponents were executed.

Moltke's mindset and his objections to orders that were at odds with international law were not without danger, and in January 1944, he was arrested by the Gestapo. A year later, in January 1945, he stood, along with several of his fellow régime opponents, before the People's Court (Volksgerichtshof), presided over by Roland Freisler. Because no evidence could be found that Moltke had participated in any conspiracy to bring about a coup d'état, Freisler had to invent a charge de novo. Since Moltke and his friends had discussed a Germany based on moral and democratic principles that could develop after Hitler, Freisler deemed this discussion as treason, a crime worthy of death. Hanns Lilje writes in his autobiography that as Moltke stood before the Volksgerichtshof, he had "possessed, in the face of clear recognition of the fact that the death penalty had already been decided, the moral courage for an attack on Freisler and the whole institution". In two letters written to his wife in January 1945 while imprisoned at Tegel, Moltke noted with considerable pride that he was to be executed for his ideas, not his actions, a point that had been underlined a number of times by Freisler. In one letter, Moltke noted "Thus it is documented, that not plans, not preparations, but the spirit as such shall be persecuted. Vivat Freisler!" In the second letter, Moltke claimed that he stood before the court "...not as a Protestant, not as a great landowner, not as an aristocrat, not as a Prussian, not as a German...but as a Christian and nothing else". He wrote: "But what the Third Reich is so terrified of ... is ultimately the following: a private individual, your husband, of whom it is established that he discussed with 2 clergymen of both denominations [Protestant and Catholic] ... questions of the practical, ethical demands of Christianity. Nothing else; for that alone we are condemned.... I just wept a little, not because I was sad or melancholy ... but because I am thankful and moved by this proof of God's presence."

Moltke was sentenced to death on 11 January 1945 and executed twelve days later at Plötzensee Prison in Berlin. In a letter written while in custody, he revealed his motivation for resistance to his two sons: "Since National Socialism came to power, I have striven to make its consequences milder for its victims and to prepare the way for a change. In that, my conscience drove me – and in the end, that is a man's duty."