The indirectly heated fixed bed reactor with particularly designed internals has been devised to achieve advanced pyrolysis performance for coal (Energy & Fuels, 28,2014: 236-244). This study extends the application of the reactor to oil shale and thereby solves the problems of low shale oil yield and low heating efficiency to shale particles in conventional fixed beds. The yield and quality of the produced shale oil and the rate heating the oil shale particles were compared for laboratory fixed beds without and with the particularly designed internals. It was shown that the use of internals doubled the efficiency of heating the oil shale inside the reactor from the heated reactor wall. Raising the heating temperature from 600 degrees C to 1000 degrees C increased the shale oil yield from 9.50% to 10.60% in the bed with internals, and reached 84.9% of the oil yield of Fischer assay (12.49 wt.% in dry base). Furthermore, the shale oil maintained its relatively stable aliphatic hydrocarbon content. In the bed without any internals such a temperature rise sharply decreased the shale oil yield from 9.53% to 4.60%. Consequently, the fixed bed with internals would be an advanced reactor also for oil shale pyrolysis, which allows high process efficiency, high oil yield and high oil quality. (C) 2015 Elsevier B.V. All rights reserved.