B. Y. Chen introduced so-called

$\delta $-invariants for submanifolds of a Riemannian manifold [cf.

*B. Y. Chen*, Jap. J. Math., New Ser. 26, 105–127 (2000;

Zbl 1026.53009)]. Generalized complex space forms and generalized Sasakian space forms have been defined by

*F. Tricerri* and

*L. Vanhecke* [Trans. Am. Math. Soc. 267, 365–398 (1981;

Zbl 0484.53014)] and by

*P. Alegre*,

*D. E. Blair* and

*A. Carriazo* [Isr. J. Math. 141, 157–183 (2004;

Zbl 1064.53026)], respectively. The authors of the present paper investigate sharp inequalities involving

$\delta $-invariants for submanifolds of both the generalized complex space forms and the generalized Sasakian space forms.