Bartłomiej (Bartek) Macieja (born 4 October 1977) is a Polish chess player who holds the FIDE title of Grandmaster (GM).

He tied for 1st-4th places with Liviu-Dieter Nisipeanu, Vlastimil Babula and Zoltán Almási at the Krynica 1998 (zonal tournament).

A four-time qualifier for the FIDE World Championship finals (Las Vegas 1999, New Delhi 2000, Moscow 2001 and Tripoli 2004), at Delhi he beat Jonathan Speelman, Michał Krasenkow, and Alexander Beliavsky but lost in 4th round to Viswanathan Anand.

[4][5][6][7] Macieja won the European Championship at Batumi 2002<[8] and tied for 2nd-3rd with Viktor Korchnoi, behind Alexei Shirov, at Reykjavík 2003.

In opening theory, Macieja has made contributions to the Classical Variation of the Nimzo Indian Defense.