The incorporation of the group VII element Br in the III-V compound semiconductors GaAs, InAs and InP and its interaction with defects was studied by means of the perturbed angular correlation technique (PAC). After annealing at 1123 K, in semiinsulating GaAs a uniform quadrupole interaction frequency νQ=299(2) MHz with an axially symmetric electric field gradient (principal component Vzz oriented along ⟨111⟩ was observed at the site of all probes. To test the relevance of this model, the appearance of the 299 MHz interaction was studied in dependence of the charge state of the probe. For that purpose PAC experiments in various predoped GaAs crystals were performed. Whereas in weakly n and p doped samples no change in the interaction parameters was observed, a new quadrupole interaction was detected in a highly p doped GaAs sample (νQ=165(2) MHz, η=0). Furthermore the microscopic environment of the Br probe was also studied in other III-V compounds. In InP after annealing at 1023 K a high fraction of the probes is subjected to a uniform quadrupole interaction (νQ=170(2) MHz, η=0), similar to the situation in GaAs. In InAs however all probes are found in a cubic environment after annealing at 923 K.