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Australian fires are a primary driver of variability in Australian atmospheric composition and contribute significantly to regional and global carbon budgets. However, biomass burning emissions from Australia remain highly uncertain. In this work, we use surface in situ, ground‐based total column and satellite total column observations to evaluate the ability of two global models (GEOS‐Chem and ACCESS‐UKCA) and three global biomass burning emission inventories (FINN1.5, GFED4s, and QFED2.4) to simulate carbon monoxide (CO) in the Australian atmosphere. We find that emissions from northern Australia savanna fires are substantially lower in FINN1.5 than in the other inventories. Model simulations driven by FINN1.5 are unable to reproduce either the magnitude or the variability of observed CO in northern Australia. The remaining two inventories perform similarly in reproducing the observed variability, although the larger emissions in QFED2.4 combined with an existing high bias in the southern hemisphere background lead to large CO biases. We therefore recommend GFED4s as the best option of the three for global modeling studies with focus on Australia or the Southern Hemisphere. Near fresh fire emissions, the higher resolution ACCESS‐UKCA model is better able to simulate surface CO than GEOS‐Chem, while GEOS‐Chem captures more of the observed variability in the total column and remote surface air measurements. We also show that existing observations in Australia can only partially constrain global model estimates of biomass burning. Continuous measurements in fire‐prone parts of Australia are needed, along with updates to global biomass burning inventories that are validated with Australian data. Plain Language Summary: Biomass burning inventories estimate the distribution and abundance of gases emitted to the atmosphere from fires. In this study, we found that three popular fire emission inventories (GFED, FINN, and QFED) predict very different emissions of the gas carbon monoxide (CO) from fires in Australia. To determine which inventory is best for Australia, we fed those emissions into global atmospheric models that combine the emissions with the chemistry and movement of gases in the atmosphere to predict the abundance of atmospheric gases, including CO. We compared the predictions to measurements in the real atmosphere. We found that GFED is better suited for Australian studies than QFED, which led to large overestimates, or FINN, which failed to capture much of the annual variation in measured CO levels. To further the outcomes of this study, more ground‐based measurements are needed in Australia, particularly in the northern half of the continent where most of the fires normally occur. In addition, the use of atmospheric models with finer resolution would also allow us to make better use of the existing ground‐based measurements to judge the reliability of different fire emission inventories. Key Points: GFED4s and QFED2.4 outperform FINN1.5, especially in northern savanna regionsACCESS‐UKCA provides a better CO simulation near fresh emissions, while GEOS‐Chem better captures variability in remote measurementsSparsity and locations of Australian ground‐based measurements offer limited constraints on Australian fire emissions in global models [ABSTRACT FROM AUTHOR]