This paper examines the relationship between the main revolutionary leftist political groups in Iran and the provisional government of the Islamic Republic of Iran under Prime Minister Mehdi Bazargan. As the first post-revolutionary government of Iran from February to November 1979, the provisional government was given the task of reconstituting the state apparatus after the revolutionary collapse of the imperial regime. This monumental task was to be done at a time when various revolutionary and moderate groups, on national and regional level, many of them armed, challenged the new order lead my Ayatollah Khomeini. Bazargan was considered a thoughtful but moderate and cautious revolutionary. His first cabinet included elements from the moderate-secular National Front. Bazargan’s prime interest was to return the country to a state of normalcy by reestablishing the state apparatus and putting the economic house in order. Yet Bazargan and his colleagues in the Liberation Movement of Iran, who was soon referred as the “Islamic liberals,” were faced with challenges which soon overwhelmed them. Part of this challenge emanated from his own fellow revolutionaries organized in the Islamic Republic Party (IRP), who viewed him as indecisive and not radical enough. A different challenge was posed by the Marxist left and militant Muslim organizations. This paper examines the relationship between radical leftist groups and the short lived provisional government of the Islamic Republic of Iran. The paper is based on the author’s extensive published research on the history of the left in Iran as well as work done by others. The interaction of five major organizations with the Bazargan government will be particularly focused on as sample. These are the Fad’iyan, the Mojahedin the Tudeh, the Paykar, and the short lived National Democratic Front. Each of these five formulated a different analysis of the Bazargan government and attempted to develop policy on that base. In this context, the hostility of Bazargan and company toward the Marxist left and his fear of being out maneuvered by the IRP caused the provisional government to make significant mistakes in its relations with the opposition. The paper will argue that this period was one of poor choices and lost chances by all parties involved.