The Accounting Principles Board (APB) was a U.S. organization responsible for issuing accounting standards before 1973.

It:

Developed accounting principles and guidelines

Issued APB Opinions

Helped standardize financial reporting practices

In 1973, the APB was replaced by the Financial Accounting Standards Board (FASB).

In simple terms, the APB was a former U.S. body that created accounting rules before the FASB took over.