Key Difference: MLA is a Member of a Legislative Assembly, whereas a MP is a Member of Parliament. As a member, their main responsibility is to partake in that legislature and help the legislature fulfill its duties. However, the terms Legislative Assembly and Parliament are the same. They are the names give to a legislature. A legislature is nothing more than a decision-making organization.

Both MLA and MP are members, which just happen to belong to different legislatures. MLA is a Member of a Legislative Assembly, whereas a MP is a Member of Parliament. As a member, their main responsibility is to partake in that legislature and help the legislature fulfill its duties.

A member must attend the sessions and represent the public’s interests and concerns in the legislature, while debating and voting on the passage of a bill, law or legislation. The roles of both the MLA and MP are essentially the same, and they differ only on the basis of the role and functions of the Legislative Assembly and Parliament, itself.

However, the terms Legislative Assembly and Parliament are the same. They are the names give to a legislature. A legislature is nothing more than a decision-making organization. It is part of the country’s government and has the power to enact, amend and repeal laws. The also have the power to create and amend budgets, as well as observe and steer governing actions.

Often the names "parliament" and "congress", are given to national legislatures, while "assembly", "diet", "majlis" and "council" are regarded as being lesser than the national level. However, this is not always the case, and the situation may differ depending on the country in question. Essentially the most common, and probably the only difference between the two is that while the name Legislative Assembly can be given to any legislature, the name Parliament is reserved for a legislature under the Westminster-style system.

Hence, only the countries that follow the Westminster-style system, and have a parliament can have a MP, which is often only the UK and Commonwealth Nations. Whereas, a Legislative Assembly can be any form of legislature in any form of government. While their roles and functions are similar on paper, the only differences that occur depend on the country in question, and the rules and regulations as governed by the country’s Constitution or as applied in reality.

Often, in countries with bicameral parliaments, wherein the parliaments (or legislature) have two houses, the term Member of Parliament refers to the members of the lower house, as upper houses often have a different title, such as senate, where the members are called the senators. However, the lower house may have a different name as, e.g. the House of Representatives, which are called Representatives. As the House of Representatives and Senate make up the US Congress, any member belonging to either of the houses is known as a Member of Congress or Congressman. Similarly, despite the fact that the House of Commons and the House of Lords make up the UK Parliament, any member of the two houses technically would be called an MP, but the term usually refers to a member of the House of Commons, whereas the a member of the House of Lords is called just that, a Member of the Lords or just Lord.

Comparison between MLA and MP:

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