The U.S. Generally Accepted Accounting Principles (GAAP) are a set of accounting rules, standards, and procedures companies use to prepare their financial statements. The Financial Accounting Standard Board (FASB) is responsible for developing and improving US GAAP.
U.S. GAAP is the standard adopted by the U.S. Securities and Exchange Commission (SEC). If a foreign company prepares its financial statements under a different standard (e.g., the International Financial Reporting Standards (IFRS), it must include a reconciliation to U.S. GAAP.