The present study aimed to assess the effect of tillage systems and crop residues on grain yield and weed infestation of spring barley. The experiment was established with the method of randomized sub-blocks. The main experimental factor was the tillage system (TS): conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The second experimental factor included plots with crop residues (CR): straw (S) or without straw (WS). A higher grain yield of barley was determined in the RT than NT system. The RT system allowed producing a higher spike number and a higher 1000 grain weight. A higher grain yield was also obtained on the plots with straw (S) than without straw (WS). Greater weed density in barley stands was determined on RT and NT plots without crop residues (WS), whereas the lowest one was found on the CT plots with the residues (S). The air-dry weight of weeds was higher on the NT plots without crop residues (WS) than on the other plots, while the lowest air-dry weight of weeds was determined on the CT plots with the residues (S). The biodiversity of weeds in a barley stand was greater on the WS than on the S plots.