5025 Mecisteus, provisional designation: 1986 TS6, is a larger Jupiter trojan from the Greek camp, approximately 50 kilometers (31 miles) in diameter.

[7] It was discovered on 5 October 1986 by Slovak astronomer Milan Antal at the Toruń Centre for Astronomy in Piwnice, Poland.

[13] On 29 November 2021, IAU's Working Group for Small Bodies Nomenclature named it after Mecisteus, from Greek mythology.

[7] In November 2009, Stefano Mottola at the Calar Alto Observatory observed Mecisteus in a photometric survey of 80 Jupiter trojans.

[8][6] CALL agrees with the results obtained by IRAS, assumes an even lower albedo of 0.0404, and calculates a similar diameter of 57.56 kilometers.