Annual crop production in California is mostly dominated by warm‐season species that require irrigation. Irrigation has been restricted due to drought and policy and may become more uncertain due to climate change. To adapt to these changes, more cool‐season crop options that require less water than summer annuals are needed. Wheat is the most common cool‐season crop, and in other parts of the world canola (Brassica napus L.), and other Brassica oilseed species have diversified and improved the productivity and profitability of cereal‐based agricultural systems. We evaluated multiple canola and camelina [Camelina sativa (L.) Crantz] varieties across diverse agro‐ecological environments throughout California. Yield potential and viability of these oilseed species as complements to wheat were assessed. Canola achieved high mean yields and seed oil content, a very high yield potential, and showed only limited genotype × environment interaction. Using short‐season spring‐type varieties and suitable agronomic management, mean seed yields could be expected to reliably exceed 3000 kg/ha, with a mean seed oil content of 45%. Camelina yields were lower (1000 kg/ha with a mean seed oil content of 30%) and more variable than canola, and displayed high genotype × environment interactions and yield instability. Camelina did not mature earlier than the best yielding canola varieties. Camelina is not economically competitive with canola or wheat, but may be viable for specialized uses in California, especially in low rainfall locations, but this requires further investigation. Given these promising results, Brassica oilseed variety evaluation and agronomic studies should continue in California.