Logical Investigations (German: Logische Untersuchungen) can refer to:
Logical Investigations (Trendelenburg), 1840 work by Friedrich Adolf Trendelenburg Logical Investigations (Husserl), 1900–1901 work by Edmund Husserl Logical Investigations (Frege), 1918–1923 work by Gottlob Frege
See also Investigations into Logical Deduction (Untersuchungen über das logische Schließen), 1934/5 work by Gerhard Gentzen