This paper proposes a method to calculate the expectation values of Wilson loop operators in the large N limit of field theories. The approach involves calculating the area of a fundamental string worldsheet in certain supergravity backgrounds. The method is applied to N = 4 super-Yang-Mills in 3+1 dimensions, where the 't Hooft limit leads to a string theory on AdS5 × S5. The Wilson loop expectation value is related to the area of a string worldsheet whose boundary is the loop. The energy of a quark-antiquark pair is extracted from the Wilson loop expectation value in the limit of large separation. The calculation is extended to M-theory fivebranes, where the area of M-theory two-branes is considered. The paper also discusses the calculation of Wilson loops in non-conformal theories associated with D-two-branes. The results show that the energy of the quark-antiquark pair scales as 1/L, consistent with conformal invariance. The method is also applied to non-conformal theories, where the Wilson loop can be calculated from supergravity when the loop size is large enough. The paper concludes that the string worldsheet approach is valid for large loops, while perturbative methods are used for small loops. The results are consistent with the expected behavior from conformal invariance and the large N limit.This paper proposes a method to calculate the expectation values of Wilson loop operators in the large N limit of field theories. The approach involves calculating the area of a fundamental string worldsheet in certain supergravity backgrounds. The method is applied to N = 4 super-Yang-Mills in 3+1 dimensions, where the 't Hooft limit leads to a string theory on AdS5 × S5. The Wilson loop expectation value is related to the area of a string worldsheet whose boundary is the loop. The energy of a quark-antiquark pair is extracted from the Wilson loop expectation value in the limit of large separation. The calculation is extended to M-theory fivebranes, where the area of M-theory two-branes is considered. The paper also discusses the calculation of Wilson loops in non-conformal theories associated with D-two-branes. The results show that the energy of the quark-antiquark pair scales as 1/L, consistent with conformal invariance. The method is also applied to non-conformal theories, where the Wilson loop can be calculated from supergravity when the loop size is large enough. The paper concludes that the string worldsheet approach is valid for large loops, while perturbative methods are used for small loops. The results are consistent with the expected behavior from conformal invariance and the large N limit.