What color do blue and orange make?
Blue and Orange make brown.

Blue and Orange make brown, #593314. That is the result in equal parts, mixing pigment rather than light - paint, ink and dye all behave this way.
Equal parts blue and orange · #593314
Change the ratio
Very little of a mix is ever half and half. Shifting the balance moves the result along the range between the two colours.
3 parts blue, 1 part orange · #39556e
Equal parts · #593314
1 part blue, 3 parts orange · #c86607
Lighter and darker
With white added - a tint · #ac998a
With black added - a shade · #351f0c
Why it works
Blue and Orange sit opposite each other on the colour wheel, which makes them complementary. Complementary pigments cancel each other's reflected light, and what survives is a muted brown. Every complementary pair does this - it is the standard way to mix brown without a brown tube.
Frequently asked questions
What color do blue and orange make?
Blue and Orange make brown, #593314. Mixed in equal parts that is the result you get with paint, ink or any other pigment.
How do I make the result lighter or darker?
Add white for a tint - here that gives sage. Add black for a shade, which gives black. Add white a little at a time, because it takes far less than people expect to shift a mix.
What happens if I use more blue than orange?
Three parts blue to one part orange gives teal. Reversing it to one part blue and three parts orange gives rust instead.
Does this work the same way on a screen?
No. Screens mix light additively, so red and green light make yellow there. These results are subtractive - paint, ink, dye and pigment - which is what people mean when they ask what two colours make.