Yes, Neandertal's brain was, on average,
larger than ours!
SOURCES:
A. africanus, H. habilis & H. sapies: Campbell, B.G. & Loy, J.D. (1996) Humankind Emerging. Harper Colins.
H. erectus: Robertshaw, P. & Rubalcaba, J. (2004). The Early Human World. Oxford University Press.
H. neanderthalensis: Tattersall, I. (1993). The Human Odyssey. Prentice Hall.