Armstrong World Industries Inc

2500 Columbia Avenue , Lancaster , Pennsylvania 17603

(Address of principal executive offices) (Zip Code)

Large accelerated filer ☒ Accelerated filer ☐ Non-accelerated filer ☐

Cautionary Note Regarding Forward-Looking Statements

Management's Discussion and Analysis of Financial Condition and Results of Operations

Quantitative and Qualitative Disclosures About Market Risk

Unregistered Sales of Equity Securities and Use of Proceeds