Both teams came through the knockout rounds which were played on Saturday in the build-up to Tigers' LV= Cup clash with old rivals London Wasps.
Newmarket came through the quarter-finals with victory over Lichfield by six tries to one and beat Nottingham 4-2 in the semi-final.
Tamworth beat Syston in the quarter-finals 2-0 and enjoyed another shut-out in the semi-final as they beat Cambridgeshire side Wisbech by the same score.
Teams representing Lichfield, Market Harborough, Newark, Newmarket, Nottingham Corsairs, Syston, Tamworth and Wisbech made it through to the last eight of the Prima Tiger Bowl and all played on the Welford Road turf ahead of the LV= Cup match against Wasps.
“All of the games were very competitive and played in a great spirit,” said Tigers community manager Scott Clarke.
“Congratulations to all of the teams who took part, and to Tamworth and Newmarket who will be joining us in the Prima Tiger Bowl next month.”
Newmarket and Tamworth will return to Welford Road for the final on February 23 as a curtain-raiser to Tigers' Aviva Premiership match with Saracens.
Now in its 19th season, the Prima Tiger Cup is supported by Prima Solutions and is open to teams from across the country, with 50 clubs entering this year.
At the next home game, against London Welsh in the Aviva Premiership on February 9, Tigers welcome the semi-finalists in the Prima Tiger Cup. The final in that competition is scheduled for February 23.
For more information on the Prima Cup, visit the community section of the club website at www.leicestertigers.com