On-farm conservation programmes require land managers to pursue both market and non-market objectives. If one can identify objectives that are complementary (co-benefits) and competitive (trade-offs) so that co-benefits can be pursued and trade-offs avoided, one may be able to lower the costs to land managers of on-farm conservation programmes.We used data from farms in northern Australia to identify potential trade-offs and co-benefits between market and non-market objectives. We used Data Envelopment Analysis (DEA) to assess the relationship between farm 'inputs' (e.g. land, labour, capital) and both market and non-market 'outputs' (used interchangeably with 'outcomes') (e.g. value of on-farm production, turtle biodiversity). The DEA analysis generated an 'efficiency score' for each farm; the best scores were associated with farms that used fewest inputs and had the 'best' outcome(s). We then looked for statistically significant relationships between those scores and other variables known to influence outcomes.After controlling for biophysical factors (e.g. rainfall, soil type), we found little evidence of trade-offs between market and non-market outcomes. We found that farms with many weeds had poor market efficiency scores, suggesting that weed-reduction programmes could generate substantive co-benefits for agriculture and biodiversity. Properties managed by people who preferred a small steady income (over a large uncertain income) had higher non-market efficiency scores, suggesting a link between conservation and attitudes to risk. Our results also suggest that encouraging on-farm agricultural diversification, the adoption of environmentally focused land-management plans, and a generally more positive attitude towards conservation could improve environmental outcomes without compromising market outcomes.