Maurice Spector (1898 - August 1, 1968) was the Chairman of the Communist Party of Canada for much of the 1920s and an early follower of Leon Trotsky after his split from the Communist International

In 1928, Maurice Spector, while attending the Sixth Congress of the Comintern in Moscow, accidentally got hold of a copy of Trotsky's Critique of the Draft Programme of the Communist International, which criticised the position of Bukharin and Stalin, and especially exposed the anti-Marxist theory of "socialism in one country". This critique was a landmark in the ideological arming of the International Left Opposition. In a truly prophetic statement, Trotsky warned that if this position were adopted by the Communist International, it would inevitably mark the beginning of a process that would lead to the nationalist and reformist degeneration of every Communist Party in the world. Three generations later, his prediction - which was ridiculed by the Stalinists at the time - has been shown to be correct.

Stalin had no intention of circulating Trotsky's document. But by a strange accident of history, that is what happened. At that time, when the Stalinist regime had not yet been consolidated, the Communist International still had to observe certain norms of democratic centralism, which permitted the circulation of minority opinions. Although Trotsky had been expelled from the Russian party a year earlier, he took advantage of the Congress to appeal to the Communist International. In the process he submitted his document on the Draft Programme. Through a blunder in the apparatus, they circulated Trotsky's document to the heads of the delegations, including members of the programme commission. It was here that the American James Cannon and Maurice Spector first saw and read Trotsky's document.

"Through some slip-up in the apparatus in Moscow," recalls Cannon, "which was supposed to be airtight, this document of Trotsky came into the translating room of the Comintern. It fell into the hopper, where they had a dozen or more translators and stenographers with nothing else to do. They picked up Trotsky's document, translated it and distributed it to the heads of the delegations and the members of the programme commission. So, lo and behold, it was laid in my lap, translated into English! Maurice Spector, a delegate from the Canadian party, and in somewhat the same frame of mind as myself, was also on the programme commission and he got a copy. We let the caucus meetings and the Congress sessions go to the devil while we read and studied this document. Then I knew what I had to do, and so did he. Our doubts had been resolved. It was as clear as daylight that Marxist truth was on the side of Trotsky. We had a compact there and then - Spector and I - that we would come back home and begin a struggle under the banner of Trotskyism." (History of American Trotskyism, New York, 1944, pp. 49-50).

Spector was a founder of the Canadian Trotskyist which was first constituted as a branch of the Communist League of America in 1929. In 1932 he co-founded, with Jack MacDonald, the International Left Opposition (Trotskyist) Canada, a section of Trotsky's Left Opposition. Spector later moved to New York City and became a leading member of the Trotskyist movement there. He presented te International Report at the founding convention of the Socialist Workers Party at the end of 1938, but dropped out of the party in 1939. (Contrary to some reports, he did not take part in the 1939-40 debate between James Cannon and Max Shachtman). He later became editor of a children's magazine published by the Labour Zionist movement.